Bitstamp does not accept XRP deposits. Bitstamp bounces XRP deposits. This is from #ripple-watch:
<ripplebot> PAY 300/XRP rKXFsg5EuG4BzLxdTBFXJq2a6iNfyx1hRX > bitstamp?dt=18081
<ripplebot> PAY 300/XRP bitstamp > rKXFsg5EuG4BzLxdTBFXJq2a6iNfyx1hRX
The first line is a deposit to Bitstamp.
The second line is the bounce.