Canuck, the X-Payments problem is very specific to your server environment. It is not a common one. I see you reported it to our techs and they are working with you in your HelpDesk account.
re: partial capturing - please check whether or not your Payment gateway supports this at
http://help.qtmsoft.com/index.php?title=X-Payments:User_manual#Appendix_A._Supported_payment _gateways - look for "p - partial transaction allowed" in "Capture" column for your payment gateway. If it is not there then your payment gateway doesn't support partial capturing, unfortunately. We added this feature to every integrated payment gateway that supports it.