Best utility to convert sql scripts from MS SQL to Oracle and viceversa

http://www.convert-in.com/mss2ora.htm

http://www.shareup.com/MSSQL-to-Oracle-download-15557.html

Free tools (Microsoft & Oracle) :

/* Microsoft SQL Server Migration Assistant (SSMA) for Oracle */
https://www.microsoft.com/sql/solutions/migration/oracle/default.mspx

/* Oracle SQL Developer Migration Workbench */
http://www.oracle.com/technology/tech/migration//workbench/index_sqldev_omwb.html

This utilities are for migrating DBs, Tables etc.  I strictly looking for an script converter from Oracle to MS SQL and viceversa.  We have a product that runs on MS SQL and Oracle.  Let's say we wrote a script to derive information from a specific DB in MS SQL, we want to be able to simple convert the script to run on Oracle, since both DBs independent of Oracle or MS SQL contain the same information, the problem lies in the syntax of the script as they differ from one DB to the other.

Ive used  Microsoft SQL Server Migration Assistant (SSMA) for Oracle, it successfully translated (approximately) 70% of PL/SQL code (some procedures/functions are very complex)