from reading their site where they have phrases like "Easy integration with almost any commerce system, order management or accounting software", "Compatibility with multiple programming languages".. it sounds like it would certainly be possible. I doubt it has been done before so you have to create this functionality from scratch.
LOL, they certainly do make a lot of promises on their site.
Unfortunately, LinkPoint (renamed to FirstData on October 2008) has the worst technical support I've ever come across from a CC gateway, as well as ZERO integration documentation. Manuals are bloody useless, and the typical hold time for support is 12-15 minutes. Not exactly the most development-friendly environment.
Well, here's hoping that someone comes across with a ray of hope regarding SilverStripe + LinkPoint. Looks like an awesome system, but if I can't get it to work with our credit card processor, I can't use it :(