You don't need to have a static IP to be able to connect to a gatekeeper.
Again, I'm not sure what you are trying to do. Are you trying to do a
"Discovering of the gatekeeper using the Gatekeeper ID"? If so the
Gatekeeper ID has to be put in the Gatekeeper ID field, not in the alias
field. The alias field is for your local alias that you are registering
to the gatekeeper.
No. Connection to GK is ok. Only I'm not allowed to use it as he doesn't
recognize GM's E164 alias. In GM preferences, on alias gatekeeper there
is info that if that alias is fulfild with only digits and #, it's
considered as a E164 ID. And on this GateKeeper, I have to register with
E164 address.