I'm having trouble with storing animation as well, my main problem is that I can't get the constraints I have on the feet to store. I rigged my model with the two end effectors at the ankles parented to two nulls that were children of the globalSRT null (I also tried this and had success using a pose constraint). This way, when the waist controller moves down the feet stay planted on the floor. The feet bones were then made children of the nulls and I could just use the two nulls to controll the feet and legs. This exports fine when animated as the default animations, but I have yet to come accross a way to store it through XSI's store functions.
Since I can load my animation in XNA and have everything translate properly, I'm assuming that the lack of constraints is a limit of XSI's store function, rather than it's ability to export them correctly to XNA (by constraints I mean the effect of the constraint, as I'm aware it's all turned into nulls anyway).
I noticed that the elastic_guy.xsi file is not rigged with any type of foot controller to keep his feet planted and make use of that IK chain. Is this because those types of constraints won't store?
Any ideas on the best way around this?