you can easily compile your projects for flashplayer 10 by adding the compiler argument -target-player 10.0.0 in the run/debug settings. no use to install an external flex_sdk. here are two lists of compiler arguments i find helpfull: http://www.flexdeveloper.eu/ and http://www.senocular.com/

the whole compiler arguments in fdt would look like this:

-target-player 10.0.0 -default-size 550 400 -default-frame-rate 31 -default-background-color 0xFFFFFF -library-path {flexSDK}/frameworks/locale/en_US