You can put the surface into the part body, even if hybrid is turned off, sort of.
With hybrid turned off....
It is possible to insert a geo-set into the part body, then paste the surface into that geo-set. This way you have your surface in the tree at the point where it was used, but you're not voilating the "no hybrids" rule that many OEM's are imposing. You're only building one tree this way.
With Hybrid turned on......
I'd do it the same way as I stated above except you must use an ordered geo-set. Don't put surface and wireframe directly into the part body, use an OGS for that.