Is there a special technique for truing flat spoked wheels? I have a set of Shimano R560's that have flat, bladed spokes (16 front &amp; 20 rear, from memory).  They are a little worse for wear after a couple of years and at least 10,000 kms.  My usual LBS has had a go at truing them but they continually go out of true just with everyday riding.  

Does anyone know of any special techniques required for these types of wheels?  

I also ask since I have another set of Ksyrium wheels, and while they have been fantastic over the past 5 years, I want to be prepared should they ever get out of true.
The only real difference is that you want to make sure the spokes don't twist. Ksyriums come with a little fork dealy so you can hold the spoke straight (at least mine did). With others, you'll have to improvise your own tool--pliers with plenty of tape on the jaws so you don't scratch the spokes would do it. Hold the spoke on the flat part nearest the nipple to keep the spoke from twisting.

Otherwise, technique should be the same.

If your wheel won't stay true, you should probably check your spoke tension. If it's too low and/or particularly uneven, you'll never get it to stay true even if you can get a temporary true on the workstand. You want to watch also for spoke wind-up, which is where the spoke twists instead of turning within the nipple and tightening or loosening. Cures for that are proper spoke prep before building the wheel, and a tiny drop of penetrating oil where each nipple contacts the rim. Penetrating oil might help if your spokes weren't prepped properly, but I don't know about that for sure.