Duplicate sales header through webservice

nXqd

I want to duplicate navision document which is sales header in this case. I try to use Copy Document function to archive the result, but i'm no luck since I have to use this function through webservice ( no form allowed )
So I have question:
1. Which is the best way to find all form which are opened so I can set `if guiallowed` to disable it in webservice mode.
( I've tried using debugger, and code coverage but it seems to be a lot of work and some of them are still left I think )
2. Is there another way to archive this. Just copy sales and bypass all validation is fine too.

Thanks for reading.