Don't ask him just yet. Stick around for awhile making quality posts and being a good member. Maybe do a few deals too, though make sure to use a good escrow. (Anyone who isn't super honest will rip you off, because you can't retaliate with a newbie account that has negative trust.)
Then, send a private message to Vod, asking him if he would be so kind as to remove the negative trust. Chances are he'll see your good activity here and happily remove it, as by then you'll have proven to be at least a semi-legitimate member.
Agreed; all anyone knows about you at the moment is that you're a newbie and you asked for a loan, but if you stick around and prove yourself to be a legitimate user then Vod will most likely be willing to remove the feedback. If you just ask now, nothing's changed from his perspective, as you haven't done much on the forum since.