Hello Donnette,
The information given is correct. Microsoft Dynamics GP is hard-coded to verify whether you're logged on as 'sa' or 'DYNSA' when attempting to access and use any of the tools in the Professional Services Tools Library (PSTL).
As a test, I setup a custom role and task for security to everything under the 'Technical Services Tools' (PSTL), and even though the user could access the PSTL window, they get a message: "You must be logged in with sa or sql permissions to utilize this Utility."
If I gave this user the 'sysadmin' SQL role, which is the equivalent of the 'sa' login, then the user could access everything in PSTL. Next, I tried removing 'sysadmin' and giving the user the 'securityadmin' and 'dbcreator' SQL roles, which is what DYNSA has, but the user got the same message as above, so the Dynamics GP application may be hard-coded to look for DYNSA and sa, then any other user with 'sysadmin' permissions on the SQL side, in order to be able to actually use the PSTL tools.
Thanks,