This may be a stupid question (to your multiple postings) but did you by any chance have your cruise control engaged. It is highly recommended that when it starts to rain you should immediately disengage your cruise control.

I live in England (where it always rains) and have never experienced hydroplaning in my xfire (we also have much faster speed limits)... but I am also very aware that cruise control in the wet can cause hydroplaning (so I don't use it when wet!).