As you slide the piston/ seal into the compression tube I use a small flat blade screwdriver to push the lip of the seal down so it doesnt get nipped off by the sharp edges. Yes this can be a slow process but care is needed!! Did you moly greasevthe inside before inserting the piston/ seal combo? Will be easier if a very light coat of moly grease is rubbed into the internal surfaces. What about sizing your seal, does it come already sized or do you need to size it first?? Once I have everything at correct size and lubricated, I add a drop of chamber lube and use a finger to wipe it all around the outside edges of the seal. The start inserting slowly, when the seal comes to an edge, use that tiny little flat blade to push the seal adge away from that sharp edge!! Keep going slowly and watch for any sharp edges comming up as it slides in. Sometimes I find it helps to rotatevthe piston a little to help it along. GO SLOW..and push that seal adge away just a slight amount so it doesnt get cut off. Good luck and let me know how it goes.
! 
