you need to starch them til they are damp and then wear them until they are dry...
i always sprayed them hanging up w/ a good coat on the back of the knees (honeycombs), the lap, and the hem... then i put them on and sat down and played some halo or something for a while until they were dry. what makes the creases is when it dries into a crease... not soaking it w/ starch, then letting it dry flat.
think about ironing w/ starch... you spray the starch on, then you iron over the starch so it dries into the fabric... if you starch a fold, then iron over it... chances are that fold is gonna stay. if you starch a flat area, then iron over it... chances are that area is gonna stay flat and wont hold a crease as easily as that place that was folded, then starched, then ironed.
am i making sense?