PAP2T connection problems

hi,
I try to configure a PAP2 adapter for use my 2 analog phones with my FrePBX - Asterisk PC.
I use FrePBX in “extension mode” and now, for problems with this configuration, I switch to “user / device” mode.
In PAP2 I have to configure:
IP proxy (or outbound proxy): my Freepbx IP, port 5060, User ID ???, Password ???, Auth user ID ???
I try all combination, ext number, login FreePBX, user name, device name, ecc.
What type of information I have to set up.
Sorry if my post, maybe, is “fresh user” question but I broke my head searching around the forums.