Then you go into to add a new alias(101x) for this set of phone logins which has this as the extension:
Then the agent logs in with 101x as the phone login and tada, it works!
Just for anybody who is as stupid as I was and to clarify things:
all the phone extensions of one alias MUST have the same "web login password"! ( Either I missed the line where it is mentioned here or people thought, it should be obvious. For me, it wasn't so this posts may help somebody someday ...)
so it is like
"phone web login" 101a with "phone web password" 101x
"phone web login" 101b with "phone web password" 101x
"phone web login" 101c with "phone web password" 101x
then agent logs in with 101x as the phone login and 101x as the phone password!
works perfectly here with vicidial 2.2.1-259. I'm going to use that feature as soon as I got the time to re-configure the phones.
Nice thing, thank you for implementing!