4
Well, host will not be off help there for sure. What you can do though is:
1.send through your host smtp
2.configure a mail server through non standar port like 2525 and send it through it, most likely your provider will not block this port. Can't remember of top of my head does XOOPS ask you for port number under smptauth or assumes it's a port 2525.
Good luck.
Gediminas