I understand what you mean with throwing it forwards, I felt the excact same about it actually. All the times I tried cork 7s the trampoline way on skis a always ate shit! But I just learned them this week and now their pretty easy, my best advice is to check out the Ask Turpin Cult and check out his threads on doing corks. Basically try a normal 7 with a reverse safety and hold the grab all they way. It worked really well for me! Also try setting the spin harder than you think but you will probably understand it if you try.
Hope this helps