Hi Jean,
Assigning FMS is a one time process.
Once you have assign an FMS to an Edit Text on a Form, this FMS will be available until you un-assign it.
Even after you restart your SBO.
Things to note is that it is attached to a specific Item UID on a Specific FormType.
You can check the FMS assigned by querying the table :
SELECT * FROM CSHS
Regards
Edy