I know this is an old post, but I'm experiencing the same issue.
Interestingly enough, I had it semi-working for a while and rebuilt the products and server and now it's producing the error listed above: exit signal Segmentation fault
Did anyone figure out what was causing this? There have been no changes/updates to php between the times that it semi-worked and isn't working now. I thought it might be a wsdl caching problem, but that doesn't seem to be the issue.
It's acting like a firewall issue, but the firewalls are completely open between the the servers. I'm not sure how or what I can do to debug the problem further.
WSP 1.1.0 (DNP) and WHMCS 4.4.2