Default Japanese ROM for X01HT - WPA2 and WM5torage problems

I just flashed a Softbank X01HT with Japanese Xbow ROM, version for foreign SIM cards since I am using it in the UK see http://forum.xda-developers.com/showthread.php?t=302785). Everything seems fine so far except for two things: It does not appear to support WPA2 encryption, which I thought was standard in WM6, and for some reason WM5torage does not work even though I have tried using it with different SD cards and different computers. Each time I get an error when the USB Mass Storage Device driver is being installed. First of all, is there a way to fix the WPA2 issue and still keep the Japanese ROM? Secondly, any ideas on the WM5torage problems?