drop the gearbox and mounts, exhaust etc and put 'em all together on the floor with the engine. Now jack the back of the van RIGHT up and get some stands/sleepers under it.
Slide the complete engine and box with all of the mounts under and then bolt up the gearbox nose-mount first. Now lift the engine up, using a second jack in addition to the engine crane to lift the sump. Place a nice big bit of wood on the sump to spread the load on the sump and jack the engine up, making sure you don't catch the coolant expansion tank (might be an idea to take it off). This should allow you to jack the complete unit into place pretty easily.
Also see the thread on here entitled sump bolt torques - IMPORTANT INFO is contained therein about a major gotcha!
thanks guys for the advice as I'm going to be working on the road side, will it no be possible to fit it in while the box in place really don't want any extra work
Thanks