Let's discuss Mass Effect.

[AD-Stu]

This is...incredibly frustrating. You can have everyone even Kasumi and Legion loyal before the suicide mission. The mission counter goes up to 2. Just leave another characters loyalty mission, besides Legion (yes even Kasumi), until after the DR and the game will give you 2 missions, notice the lack of loyalty, before the suicide mission scenario kicks in. I've done this 9 times, the other 3 times I played through ME I purposely killed some squadmates. I know this is possible, you're doing something wrong. And it seems to be that you do every possible loyalty mission before the DR.

Yes the addition of Kasumi changed things a bit and the solution to this problem like I stated earlier is the leave another LM besides Legion to do after the DR. That is all. The game will give you enough time to do two missions, which is just enough to complete Legion's LM and that of the other character whose LM you chose to leave uncompleted. If you still think this isn't true then your game must be broken or I'll have to refer you the the ME wikia because I can't explain this to you.

http://masseffect.wikia.com/wiki/Mass_Effect_Wiki

Just to throw a spanner in the works, I'm pretty sure I've never had to do it this way to get a perfect result. I've always done all the loyalty missions (including Kasumi's), then the derelict Reaper, then activated Legion, done his loyalty mission and then had the kidnapping scenario runs.

I could be wrong, but I think there might be an issue with when exactly you activate Legion - pretty sure you have to activate him and talk to him (possibly talk to him multiple times) to get his loyalty mission in your journal before you touch the galaxy map. If you do that you should be given time for his loyalty mission. If that doesn't happen, I think there's something wrong with your copy of the game.