Interesting mod. It does not replace existing aircraft (except for Su25)
http://forums.eagle.ru/showthread.php?t=83647

The aircraft are:-

- Rafale (versions C, B et M)
- Mirage 2000 (version B, C, D, N et -5F)
- Mirage F1 (versions C, C200, CR et CT)
- Mirage IV-P
- AlphaJet
- Jaguar A
- SEM (Super Etendard Modernisé)

are there any missions for this anywhere?

I've installed the mod but can't figure out how to actually fly any of the aircaft.

I've no idea how to use the mission builder. everytime i select the Mirage 2000 N or whatever it just flies around and i can't get into the cockpit.

Hi,
in the mission generator, just select "Player" as skill: you'll fly the plane :-)
Otherwise, there are some missions together with the mod.
Good fly!

Many thanks