OL2003 custom form saved as template

[Guest]

After adding the From field to a form, with the initial value of the text
field set to a string that resolves to a non-person email account/address,
and saving as a .oft template file, only I can send messages with this
template. Anyone else in my group receives "You do not have the permission
to send the message on behalf of the specified user", including the mailbox
owner. We don't want to make this a published form, just a template file
that only our group knows about & uses. What's happening from stopping my
coworkers from sending with this 'From' customized message (esp. the mailbox
owner!)?

 

[Guest]

additional observation: even without automatically adding the From field
configuration & value in a saved .oft, a manually inserted 'From' address
(the non-person mailbox) is unable to be used (i.e., Send attempt generates
message) by everyone except me (the .oft creator). The address is selected
from the Global Address List.

How should the .oft be created so anyone can use it along with the From
field with the generic address?