I can’t believe I didn’t think of this earlier. It’s simple to change the keyboard shortcuts in FlexBuilder so I changed the “Run” keyboard shortcut from Shift + F11 to Ctrl +Numpad_Enter. That’s what I was used to in the Flash IDE. And I changed Debug to Ctrl + Enter. It’s a small change but makes FlexBuilder seem a little more familiar.

Go: Window -> Preferences… Expand  General and select Keys. Then just  scroll down to Run. ( To get there faster type run into the “type filter text” field and then scroll. )

And it’s not a bad idea to scroll through the, rather long, list of actions that can have keyboard shortcuts. There’s a bunch of things in there I didn’t even know FlexBuilder could do.