Thanks for your reply.
It was the answer I feared, but eh 
.
I think I'll go for a 10 setInterval call I think, and thus if nothing is found, well I'll accept the fact that no data source has been bounded.
Anyway, the matter of time before the set executes and the get retrieves the value is very short, if you delay the runtimeHandler for 0.5s, seems like the data are always already set (maybe it depends of the size of the data source).
Imo, the component part misses a callRuntimeHandler that would work the same than APS, but in the other way around.