Including exteral .as files and, why aren't my .as files using AS3?

programming flash
1

Question 1: I need to include up to 3-5 external .as files in my main .fla,
However, include doesn’t work in AS3, so how do I do this?

Question 2: everytime I make a actionscript file (.as) in adobe flash 9 they’re always using actionscript 2.0, how do I change this!, it counts AS3 code as syntax errors!!!

Any idea’s,

Thanks in advance