Microsoft Office Compatibility Pack on MS Server 2008 with Office 2003 - does not work? Alternative solution?

Hi.

We have a Citrix server on a MS 2008 server, which, among other things, offers Office 2003 to the citrix clients.
Now, we want our clients to be able to open docx documents, and have therefore installed the Microsoft Office Compatibility Pack (http://office.microsoft.com/en-us/word/HA100444731033.aspx) on the server. It just does not work (the office 2003 is fully updated). Word, for an example, cannot open or save docx documents, it just posts a brief error message saying that it could not open the document.

On the MS download page, MS 2008 server isnt listed under supported operating systems, which may be why it does not work?

So is there a workaround on this? Or a possible alternative, which doesent include fixing on the client side?

Thanks alot!