Thanks a lot. I were not able to find any usable rpms myself, before I knew some name to search for. Looks like this is the link. xxhttp://atrpms.net/name/asterisk/
By the way I have tested a dedicated virtual Asterisk installation the latest days, but I guess it will be more reasonable to implement this fuction into the SME 7.3 server.
I am rather surpriced that voip and Asterisk works well enough, when installed as a virtual installation, but I actually I think it works, bether than first expectec.