Hello.
Attached you can find a patch file which updates welcome.py so it would contain the required details for a bot to work with Persian (fa) Wikipedia.
I opened a request on the bug tracker (on SourceForge) today in this regard as well, but Merlijn told me to create a patch for it. The current patch is more complete that what I sent there. With this patch, that bug is obsolete, so treat it is you should.
Best regards,
Huji
pywikipedia-l@lists.wikimedia.org