Illusions in combat?

[washout]

How do illusionary attacks work? I seem to recall that you take illusionary damage over time and can "die" from it and then wake up when the illusion fades, but the 3.5 srd contradicts that pretty comprehensively. So if I create an illusionary monster and then hit people with it does it have any effect whatsoever? Can an undetected illusion act as a flanker? What exactly can undetected illusions accomplish in real combat situations?

 

[Kmart Kommando]

Depends on what type of illusion it is.
Figments and Glamers do no damage.
Phantasms do real damage if the target believes it is real.
Shadow illusions do real damage, even if revealed as not entirely real, they just do less than full damage if disbelieved.

Figment creatures should be able to flank if they are believed to be real.
Phantasms are real(ish) to the subject, but no one else can see them, so they proably won't be flanking buddies.
Shadow creatures are partially real, so they can be flanking buddies.