I have no idea how you would do it with a virtual account. I have been compiling and trying it on a dedicated machine. ie. I have root access. So with root access just recompile with standard flags plus the extra ones...
What do --with-dom and --with-qtdom do?
I haven't compiled with thoses, what am I missing out on?
You could try asking the person that runs your server if they will recompile with the extras you are wanting (you had better have a good reason why you need them though). They are bound to re-compile it and re-install it every so often when patches come out. I have found when you ask web hosts technical questions they don't know the answer and give a silly answer. I think it is just sales people answering tec support questions but either way it is very hard to get anywhere.