Replacement Dometic 300 series toilet water valve

I've got to take part of the blame for this one. I was assured by several people that the dometic 300 was a plug and play replacement for my unit but the supply line faces the rear as opposed to the side like the old one and even with the shallowest elbow I could find it still tweaks the valve assembly on a rear bulkhead when in use. I thought I shaved enough off the bulkhead but apparently not. More exacto knife required.