Custom aggregation and Parent-Child hierarchies, do they work together?

[prikala]

I am trying to implement a Dynamic Cube that is using externally
rolled up fact (similar to Transformer and External rollup).
Using Custom aggregate should give the desired functionality.

It seems to work ok if using regular dimensions.

But values are NULL if I try to use a Parent Child hierarchy.
So the question: Do Custom aggregation and parent Child hierarchies work together?

Why parent-child hierarchy? In my fact I have a value for every member in every level of the hierarchy.
With parent-child hierarchy one join would be enough to join dimension to fact.

I think (have not tried yet) that when using regular dimensions, I must use different fact for every level. And when using dynamic cubes, different facts mean virtual cubes etc...