mISDN echo problem and possible use of OSLEC


I’m using Elastix 2.03, Asterisk with an Atcom AX-4S card (4xBRI).
I have installed the card using mISDN 1.1.9 and everything is working fine except there is echo on some calls.
Is there a way to make my system use OSLEC?
I read a lot about a patch that lets mISDN use OSLEC but unfortunately there is no such patch for mISDN 1.1.9.
I found a patched mISDN version 1.2 and wonder is it possible to install mISDN 1.2 on my system?
Or is there something else I could do to reduce the echo?

Once again the system is:
Elastix 2.0.3
uname -R gives back: 2.6.18-238.19.1.el5

Thank you in advance for taking the time to respond.