Creating custom forms in Outlook is pretty simple, but the problem I ran into is that my signature was being put in the Message body every time. I did a little searching and found the solution to remove the signature from the custom form.
1. Open the form in design mode.
2. Run the form.
3. Delete the signature.
4. Use the “Design This Form” command to open the form again in design mode.
5. Publish the new form, which should no longer have the signature in it.
The original post where I found this is here. They listed something about versioning control, so if that’s something you’re interested in, check their post. I don’t need versioning control so I was able to use the 5 steps above.
Source: Ramblings o’ Techie