SBS 2008 Exchange Logs not clearing after Full Backup

Experts,

We have taken over support of an SBS 2008 machine and the Exchange transaction logs are not being cleared even after FULL SBS 2008 Windows Server Backup on a nightly basis.

I have compared the VSS writers between this SBS 2008 and another one. On the problem SBS there are only the following writers:

Writer name: 'ASR Writer'
   Writer Id: {be000cbe-11fe-4426-9c58-531aa6355fc4}
   Writer Instance Id: {07084cbf-098b-4701-8a01-279befc28e78}
   State: [1] Stable
   Last error: No error

Writer name: 'Registry Writer'
   Writer Id: {afbab4a2-367d-4d15-a586-71dbb18f8485}
   Writer Instance Id: {061b346b-400a-4f44-af06-b01e42aa7e65}
   State: [1] Stable
   Last error: No error

Writer name: 'Shadow Copy Optimization Writer'
   Writer Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
   Writer Instance Id: {719f9c11-0cdb-41ee-84dd-323fc13e5fd2}
   State: [1] Stable
   Last error: No error

Writer name: 'COM+ REGDB Writer'
   Writer Id: {542da469-d3e1-473c-9f4f-7847f01fc64f}
   Writer Instance Id: {bb6d38a7-71d0-43e9-addc-152581aa3a4a}
   State: [1] Stable
   Last error: No error


On the working server there are a great deal more writers:

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2005 Microsoft Corp.

Writer name: 'System Writer'
   Writer Id: {e8132975-6f93-4464-a53e-1050253ae220}
   Writer Instance Id: {60c18ad8-2c87-4c91-a8b4-be8271ff1d51}
   State: [1] Stable
   Last error: No error

Writer name: 'SharePoint Services Writer'
   Writer Id: {c2f52614-5e53-4858-a589-38eeb25c6184}
   Writer Instance Id: {b662770c-ff6c-486e-939c-13cfcfb0e74b}
   State: [1] Stable
   Last error: No error

Writer name: 'SqlServerWriter'
   Writer Id: {a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}
   Writer Instance Id: {bb4b5d33-c086-4603-8ac3-678d4baed225}
   State: [1] Stable
   Last error: No error

Writer name: 'ASR Writer'
   Writer Id: {be000cbe-11fe-4426-9c58-531aa6355fc4}
   Writer Instance Id: {2c17cee9-a8b5-4506-b719-16a794a1cba2}
   State: [1] Stable
   Last error: No error

Writer name: 'FRS Writer'
   Writer Id: {d76f5a28-3092-4589-ba48-2958fb88ce29}
   Writer Instance Id: {b2b03188-8da7-4e76-a081-847ab71c1593}
   State: [1] Stable
   Last error: No error

Writer name: 'FSRM Writer'
   Writer Id: {12ce4370-5bb7-4c58-a76a-e5d5097e3674}
   Writer Instance Id: {c4fe32ce-d933-4f26-91bf-3bf315fd6dc1}
   State: [1] Stable
   Last error: No error

Writer name: 'Dhcp Jet Writer'
   Writer Id: {be9ac81e-3619-421f-920f-4c6fea9e93ad}
   Writer Instance Id: {0302e9f7-37eb-4c86-b95c-694a35044a57}
   State: [1] Stable
   Last error: No error

Writer name: 'IIS Config Writer'
   Writer Id: {2a40fd15-dfca-4aa8-a654-1f8c654603f6}
   Writer Instance Id: {3975dd2f-668e-4d64-9512-c9baa1c007fc}
   State: [1] Stable
   Last error: No error

Writer name: 'Microsoft Exchange Writer'
   Writer Id: {76fe1ac4-15f7-4bcd-987e-8e1acb462fb7}
   Writer Instance Id: {c0613cdc-c0fe-4c4f-bbab-61ea9539b4ba}
   State: [1] Stable
   Last error: No error

Writer name: 'Certificate Authority'
   Writer Id: {6f5b15b5-da24-4d88-b737-63063e3a1f86}
   Writer Instance Id: {91cb4cbb-53d5-4a57-8de6-54bc860879af}
   State: [1] Stable
   Last error: No error

Writer name: 'Registry Writer'
   Writer Id: {afbab4a2-367d-4d15-a586-71dbb18f8485}
   Writer Instance Id: {4ba3ea8e-06da-41f6-b712-3ca5b9ff7f7b}
   State: [1] Stable
   Last error: No error

Writer name: 'NTDS'
   Writer Id: {b2014c9e-8711-4c5c-a5a9-3cf384484757}
   Writer Instance Id: {348f4977-0826-4062-a43d-e2020006535a}
   State: [1] Stable
   Last error: No error

Writer name: 'SPSearch VSS Writer'
   Writer Id: {57af97e4-4a76-4ace-a756-d11e8f0294c7}
   Writer Instance Id: {61f1c09f-5752-4ede-90a3-26e7b33fcbcd}
   State: [1] Stable
   Last error: No error

Writer name: 'NPS VSS Writer'
   Writer Id: {35e81631-13e1-48db-97fc-d5bc721bb18a}
   Writer Instance Id: {e5c828ba-29f4-4b84-af08-d304e4b9b8d8}
   State: [1] Stable
   Last error: No error

Writer name: 'COM+ REGDB Writer'
   Writer Id: {542da469-d3e1-473c-9f4f-7847f01fc64f}
   Writer Instance Id: {63a56723-e903-43d7-a676-959140a8bdf0}
   State: [1] Stable
   Last error: No error

Writer name: 'TS Gateway Writer'
   Writer Id: {368753ec-572e-4fc7-b4b9-ccd9bdc624cb}
   Writer Instance Id: {bae802d8-4c39-45e8-9b2a-1a9ff6bcb6f9}
   State: [1] Stable
   Last error: No error

Writer name: 'IIS Metabase Writer'
   Writer Id: {59b1f0cf-90ef-465f-9609-6ca8b2938366}
   Writer Instance Id: {dd91915d-2808-473c-a935-12435da87a79}
   State: [1] Stable
   Last error: No error

Writer name: 'Shadow Copy Optimization Writer'
   Writer Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
   Writer Instance Id: {86615212-cb35-4bc1-8d1b-b5f5781603ba}
   State: [1] Stable
   Last error: No error

Writer name: 'WINS Jet Writer'
   Writer Id: {f08c1483-8407-4a26-8c26-6c267a629741}
   Writer Instance Id: {0a52a170-4cc6-47e4-a378-e94f0b016382}
   State: [1] Stable
   Last error: No error

Writer name: 'BITS Writer'
   Writer Id: {4969d978-be47-48b0-b100-f328f07ac1e0}
   Writer Instance Id: {2ec690db-9d5b-4d21-aad4-cae0fb88d768}
   State: [1] Stable
   Last error: No error

Writer name: 'WMI Writer'
   Writer Id: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0}
   Writer Instance Id: {8bf227f7-c2dc-46f9-8bcd-2f4348a7df5f}
   State: [1] Stable
   Last error: No error


They previously used Storagecraft Backup before we took over however we preferred to use the build in tools. Could it be that the missing VSS writers (exchange in particular) has meant that the logs are not being cleared up until the last known full backup?

Could Storagecraft have removed the built in writers and used it's own?

How would we repair/replace the missing writers?

The Exchange Server 2007 is only on SP1 build level but the Exchange aware issue mentioned here did not affect SBS 2008:

http://blogs.technet.com/b/exchange/archive/2008/06/18/3405615.aspx

We are hesitant to install the latest SP's and RU's given there are writers missing.