I have a small ARexx-script that adds my menus:
/**/
PARSE arg Command
ADDRESS Workbench
OPTIONS RESULTS
MENU ADD NAME svnadd TITLE '"Subversion \Add"' CMD 'svn.rexx add'
MENU ADD NAME svnupd TITLE '"Subversion \Update"' CMD 'svn.rexx update'
MENU ADD NAME svncom TITLE '"Subversion \Commit"' CMD 'svn.rexx commit'
MENU ADD NAME svndel TITLE '"Subversion \Delete"' CMD 'svn.rexx delete'
This adds four commands to a submenu "Subversion".
I then run this at the end of my startup-sequence.
Got the ARexx commands from the OS3.9 HTML manual.