Andrew R Stewart 

The cassette is held onto the freehub body with the splined ID locking cap/ring, just outside of the axle end that is circled in red. Just like a standard hub set up. What is different is that RH axle end, compared to common loose ball hubs. IIRC Mavic's right side axle end cap retains the freehub body (and this is maybe what the OP was referencing when they mentioned "tightening up the cassette"). I believe this RH side of the system is not adjustable and the axle is not threaded to achieve this, only to bottom out the RH end cap to secure the FH body. It's the LH side that the bearing preload is done at. The cartridge bearing rides on a sleeve that threads onto the axle and the lock nut traps this. But there's some aspect of this system that is compressed/deformed so that it is not to be reused after removal (unlike previous Mavic pin tool worked preload rings). (When I was explained this years ago I rolled my eyes at the need to replace parts when a bearing adjustment or replacement was done. They claimed lower cost to produce the hub, yet the shop or customer would bear the cost done the road during maintenance). I could have some of this wrong, it's been quite a few years. But it should be a simple discovery to remove the RH axle end cap and see if it's reversible and thus if that will allow it to enter the drop out slot. Andy