IB never reported historical volume on Forex financial instruments. It was always reported as -1. This is by design.
If you want historical volume you need to request historical data for Forex futures/ETFs/options, etc...
The trading hours' information for any financial instrument is available in TWS (mouse right-click over the instrument row).
The exchange for EUR.USD is IDEALPRO (or IDEAL).
Hope this helps.
--
