Evilbunny of the e164.org forum mentioned the dyndns option again to me.
Using the dyndns option is for me far more easier than "rerouting" everything through voxalot. Just entered for my numbers at e164.org
myvoipnumber@myhostname.dyndns.org and everything works flawlessly.
All the calls (my configured e164 numbers resolved through e164.org) are being forwarded to my FB7050 and my phones will ring
(a happy) Gusman