Re: Anyone else having trouble with Bitstamp Ripple transactions?

But they immediately convert the fiat currencies to USD, don't they? I haven't seen any EUR IOUs.

They exist. The transfer to/from Bitstamp puts them into/out-of your Bitstamp USD balance.

See https://ripple.com/forum/viewtopic.php?f=1&t=2008#p3870 for details.