well heres what I do.. maybe it will help?
Draw the background in flash with the line tool, because usually the scenerey is rooms or buildings ect which need lots of straght lines and correct perspectives. Its easier for me to do that with the line tool.
fill in basic colors, then export the frame as a png, and import into adobe photoshop and add all desired details and colors.
not only does it looks better, but its less likely to lag up the scene in flash since there is no vectors to process, and flash can focus on the actual animated characters.
hope that helps.