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Is this administrator managing the site for you? I mean are you paying him/her to manage your site?
Otherwise, even if what you're asking isn't difficult maybe the website owner manages the site when he/she has some free time and maybe they're busy right now. I have several sites that I don't make money with and manage in my spare time. Lately I haven't had a whole lot of spare time so the site suffers.
It's also possible what you're asking is beyond the experience and knowledge of the website manager. XOOPS is pretty easy to setup so just about anyone can do it. But modifying it is another story. Some modules break other modules, you have to be aware of version issues and more. If someone just uploaded XOOPS and customized it some, I wouldn't assume they're comfortable enough to do what you're asking.
Lastly, consider offering to help. Do some leg work on what would be involved. Instead of demanding the manager do this for you, ask nicely, be very patient and offer to help out. You might get better results.
Good luck
"I'm going to see if this internet thing takes off" - someone told me this when I suggested he needed a website.