Need to edit Custom Attributes in Active Directory Users and Computers for Non-Mail enabled users

Hi
We have an active direcotry domain running on Windows Server 2003.  We have around 5000 users and a third of them are non-mail enabled users.  

For the Mail enabled users we have been using one of the extension attrbutes to contain their employee id.  A new initiatve is making so that the non-mail enabled users need to their employee ID set.  Is there any way to modifiy the custom attributes in the ADUC for a non-mail enabled users.  

 I know I can write a script to do this or use ADSDIEDIT, but it is for our account managment people and they need a very easy interface.   I have done research and some say you can create a custom tab but I do not have any windows C++ programming experience..

Thanks for any assistance
Jon Page