Stuck at surfacing

Hello folks, I am a student in Industrial Product Design, at the moment I'm modelling a hunting knife in Solidworks

I made a real size model out of ploystyrene foam. Now I've done pretty wel in reconstructing all the surfaces (using the loft command), but I really got stuck at that curve where my thumb is supposed to fit...I haven't really had a course at freeforming yet so I'm trying to find my way with lofts and sweeps, cut extrudes and other basic comannds. If any of you have suggestions on how to fix it, they will be very, very welcome!

I will include some pictures to help visualise the situation.

http://i155.photobucket.com/albums/s311/Yev300/401643_4015943523114_1417112814_33517751_1460779339_n.jpg

http://i155.photobucket.com/albums/s311/Yev300/Kalashnikov_Eugeny_Handen_Jagersmes.jpg

Thanks for your time!

SolidworksSurfacing