I mean, if you try to create a fictive SIP provider, is the text field missing too?

Hi Sebastian.
I will create a fictive SIP and IAX provider to test. I will mention however that the missing field behavior did not manifest it's self immediately. I cannot not tel you exactly when the text field became missing.
Apparently the Soekris 4801 boards have issues with flash based CF cards and DMA. Because of this (I think), i couldn't use any of my 4Gig CF cards; so I did a fresh install on a normal IDE HD. I reentered my config from scratch (not a restore from backup) with one difference.
I did not leave the "Incoming Extensions" field blank as i did before. I populated it with my DID. Several days and reboots later, the text field is still visible.
Over the next few days, I will test leaving the "Incoming Extensions" field blank on the fictive providers and will report my findings.
Thanks.