Basically you can use any memory manager with madExcept. You just need to tell madExcept about it. You have 2 choices:
(1) In the madExcept settings turn the unit init order patching completely off. This is the easiest way to make all memory managers work with madExcept. You'll lose a tiny bit of madExcept protection this way, but it's not much.
(2) Or enter the memory manager units in the correct order into madExcept's unit init order patching edit box. Can be difficult, if the memory manager involves many units.
Personally, I'd say just turn unit init order patching off, then the memory manager should make no problems with madExcept.
If it's just one unit then simply add it to madExcept's unit init order patching edit box. If it's more than one unit, then it gets more complicated. The author of the memory manager can't help here. I'd need to analyze that.
But as I said, you can simply turn unit init order patching completely off, then it should work anyway.