well, considering its bleem, why dont you try converting those dexdrive saves into bleem saves?
you can use a memcard manager to do it, such as the one on
www.aldostools.com
however, you hafta remember that the vmu must be clean for it to work. and at least im not even sure what kind of format the bleemcast actually saves in so this might not even work at all. what you can do to test is to get a save onto your vmu and maybe upload that and try it out on bleem.