Yes, click on your sketch of what you had extruded or simply click share sketch to extrude to whatever plane you need it to. Sorry I am not really good explaining but hope it helped.

You should be able to do it, i just tried it right now. Okay if we are on the same page or what you wanted, this is what i did: you offset your plane from the edge or curved plane you want your sketch to be. after you pick that sketch and complete it, you extrude your sketch and pick distance (either) from or to your curved surface. and that shouls work.

Yes, it`s possible. I`m working with Autodesk Inventor 2010, and I gota extrude from a sketch to a surface.
Try the following suggestion:
1. You need have two skecthes, the first is a profile and the second is a surface.
OBS: The Surface size need be bigger than or equal the skecth profile.
2. Select the extrude tool.
3. Change "Extents" for "to".
4. Select the firdt profile.
5. Select the referece Surface.
6. Click OK.

If the text was a little confuse, alert me, that I post the images about it.

Hey Brian I totaly agree with Kobus Erasmus, unless you want to avoide redrawing old sketchs or just want a faster way. I usually copy paste or ctl c.