this may sound like a very simplistic approach, but it can be helpful in using scales that you are not used to. it is how a friend of mine pushed me into playing leads back when i couldn't .
but it takes restraining the natural urge to shred. :)
record the chord progression you want to do a solo over, so you can play it back to jam over.
find two notes in the scale you are tring to use that sound good over the chords. attempt to make a two note guitar solo, being as creative as you can with those two notes, using bends or different picking, get different sonds on the same notes. obviously you will get bored with this quickly, but give it an honest effort. when you can't stand it anymore, add another note, and work with those three.
this actually helps you get a feel for timing, and playing notes that sound good at the right time. don't be surprised that if you give it an honest effort you won't have to keep adding one note at a time through the entire scale before you get the feel for it. another thing to keep in mind. you do not have to play every note of a scale, just because you are using a scale.
three notes that sound good goes a lot further than five that don't.
hope it helps you as it did me.