Whether you have a track record or not, you need wealthy contacts to raise money. Unless your marketing guy has the right contacts, he will fail.
You're probably best to put him on salary plus commission. If he can't prove himself in 12 weeks, get rid of him. About 12K base for the first 12 weeks with the opportunity to triple it if he can bring in a couple of million.
If he can't raise $500K in that time, he is full of shit.
Runningbear