Sorry for the delay...
I've checked the site you supplied and I can confirm that this is an issue with SiteImport. It should be recognizing this type of linking. I'll be checking into the code to see where SiteImport should be finding these links to add to the list of files to download. I'll post back when I've been able to get a fix checked in. From there we'll need to do a little testing to insure that we didn't introduce any other issues with the fix, we'll then get a new build out to users. Just to let you know that will be at least a few days once we've identified a solution before a new build will be distributed, but I will keep this thread updated.