ApplyUsageRights returns empty binary data

All,

  I'm just starting to play with LiveCycle, and I started with the ReaderExtensionsService applyUsageRights. When I send my webservice call from ColdFusion, I'm getting a BLOB back but the call to getBinaryData() returns empty.  I've tried sending a pdf as binarydata and as a URL, with the same result. I tried sending junk data, and it correctly returns error messages.

Any suggestions for debugging this? I'd much rather see errors than simply empty data.

marc