Esri Programming blues

I just have to vent here. I have had it with ESRI's documentation for ArcObjects. Many objects have no significant document page on the online help. The pages are just place holders for more documentation on the object. It's really all very useless.
I am stuck on using the new geoprocessing functionality. Like Union, Intersect etc...
The docs say that all you have to do is create a dispatch object and that object has all the functions on it.
But it doesn't work with SDE layers for some reason. There are exmples a-plenty for shapefiles and personal geodatabases, but none for SDE. Nothing on ESRI's support website. Nothing on the ESRI-L. I feel like I'm out in the cold on this one.