Try
print $resp->{xmlref}{Details}{ReleaseDate};
And then read references quick reference (Re: push)
Examine what is said, not who speaks.
"But you should never overestimate the ingenuity of the sceptics to come up with a counter-argument." -Myles Allen
"Think for yourself!" - Abigail
"Time is a poor substitute for thought"--theorbtwo
"Efficiency is intelligent laziness." -David Dunham
"Memory, processor, disk in that order on the hardware side. Algorithm, algorithm, algorithm on the code side." - tachyon