ThinApp Acrobat Reader 8.0 & IE7 Issue

Hi,

I have used ThinApp to capture Acrobat Reader 8 and have then used ThinReg to install onto a client and I can open PDF documents ok. 

However when in IE7 (full installed version, not ThinApp'd), if I try to open a link to a PDF document, instead of the PDF document opening within the browser as would usually happen with a full install of Acrobat Reader, I get a "File Download" dialogue box with the options to Open or Save.  If I select either of these I can then open the PDF outside of the browser.

To get one of our applications working I need the PDF documents to open within the browser window.

Any ideas?

Thanks

Mark