Hi There,
A long time ago, I believe there was an issue where /V didn't properly handle this when using a response file.
From a little bit of testing, at least, it looks like their setup might have a problem with the way its been authored. I'm unable to get an *.iss file to run the setup silently, correctly.
Although, for what it's worth, I can actually see the property I'm passing via /V getting passed OK:
XEUniv.exe /s /f1"c:\oracle.iss" /v"MYTESTPROP=1"
As you can see, I'm using the "Universal" release of the express 10g database.