How to interface Asterisk with an Elmeg ISDN T240

We are trying to interface an Elmeg T240 on an Asterisk system with an Junghanns QuadBRI card.
Dialing into the Elmeg with 2 connected phones on the a/b ports 1 and 2 works, no problem there.
Trying to dial from the Elmeg to the asterisk or outward, we don’t even see a request for a line or whatsoever in the logs and console of the asterisk.

We had similar issues with a similar setup with a Tenovis/Bosh Integral system, where we had similar behaviour…

Is there anyone here that did the same trick, and managed to get it working?
Please send me a description of what to check, and how you managed to run the systems interconnecting with each other…

Thanks guys!