Integration Siemens Hipath 3800 & Asterisk 1.4.44

Hi everyone,
Please, pay attention about my problem. Thanks in advance.

Debian 6;
Asterisk 1.4.44;
Libpri v. 1.4.12;
Dadhi v. 2.6.1.x;
SNEP Livre (as Asterisk GUI - v.1.3.8);
Hardware: Khomp K2E1-SPX (PCI-ex)

Goal: PABX Siemens HiPath 3800 and Asterisk 1.4.44 integration

To run this solution, some parameters must follow the model below:

PSTN -> HiPath 3800 -> E1 <- Asterisk

We started out our tests using Asterisk under ISDN protocol as well as signalling source timer. We got connection between asterisk and hipath configuring 2 extensions (1 extension configured on HiPath and other in asterisk) and the phone call just occured succesfully.
As you can see, we got connection but in a inverse mode. We need to talk using HiPath 3800 as master (source timer) and Asterisk as slave.

By the way, to integrate these solutions is our first step to migrate all HiPath 3800 PABXs to open source solution (asterisk).

We tried to search on the web several times. Our efforts mustn’t in vain but a couple of tips were found and not so clear.
We appreciate any suggestion/help.

Best cheers.

P.S.: Sorry about my english skills. I need to improve it.