Hi friend, how are you?
I work at the "real life" in the fields of IP telephony and virtual networks. I installed Elastix often, especially version 2.4 and sometimes 2.5
With respect to the virtual fax, I managed to install it. But only domestically enters different virtual IAX2 extensions. Nothing hardware for now.
If you want help, I'll need to know the version that manages your Asterisk and Elastix.
We can talk at any time over IP telephony, sharing knowledge is good hehe.
Best regards,
Claudio Ruggiero.