Edit Share permissions using batch file?

[Crispin]

We have recently moved over files for students and staff from a 2000 to 2008.

NTFS permissions on the folders are set correctly using cacls to give users modify rights.

However the share permissions are only set to "Administrators - Owner" and "Users - Read".

What is the best method to perform something similar to cacls to give users share permissions with 'modify' rights?

I've googled quickly and come up with rmtshare but not sure if its included in 2008 or if its scriptable.

Any suggestions?

EDIT: Just found the answer to this elsewhere on edugeek, sorry!