There is a phillips head screw holding the lock blade in place. If you can get to it, unscrew that and the blade will fall off allowing you to open the hatch.
For a replacement, go to CH751.com and replace the whole set of locks. The locks you have, have millions of keys, so just about anyone can unlock them. The website will walk you through how to measure, etc. You can call them and they will walk you through it, also.
I've replaced the locks on each trailer I have bought. I don't want my stuff disappearing. I know there are people who swear they have never had anything disappear, but I'm not taking the chance.
How many of you would think it odd that someone was opening the cargo compartment with a key? No one. Now, if they are trying to use a crowbar, etc. of course. Therefore, I take away the "not suspicious behavior" from the equation and the person is not likely to try to get in to take the stuff. Plus, I have seen a couple of owners try to collect on insurance, where there is no proof of a break in. Not fun.
Ben and Doreen
Home Away From Home - 2017 PT Crusader 315RST
TV - 2008 F250 Lariat 4X4 6.4 Diesel
42 nights camping in 2015
49 nights so far in 2016 (Still Not Enough!)