Change generated pdf filename in broswer save as

Hi there,

I am wanting to be able to set the filename of the pdf when the user 'saves as' in the browser.

Currently the form renders as:
http://[server]:8080/DocumentManager/docm1367214844093/ecc9ed6e38a6d49 14c0653ff65d88938?type=YXBwbGljYXRpb24vcGRm

and when the user hits the 'save' button in the browser toolbar to save the file locally. The filename generated in the save dialogue box is ecc9ed6e38a6d4914c0653ff65d88938.pdf

Is there a way to change this to [somefilename].pdf rather than manually having to set the filename each time the user wanted to save the pdf.

I have tried a few things including setDocAttribute(/process_data/@document, 'basename', "somename.pdf") as both an execute operation and as an XPath expression in the renderPDFForm operation. But nothing has worked so far.

Does anyone have any ideas to point me in the right direction.

cheers,

Paul