I use the Business Productivity Workflow Tools to accomplish the issue to get an GUID in a workflow.
But now I've the following problem.
I use the GUID to concatenate with a hyperlink for my custom website... in an e-mail.
But the part of the hyperlink after the ID parameter doesn't work. So I get a piece of the hyperlink underlined.
Example:http://dynamicscrm:5556/Default.aspx?ID ={Case GUID(Case)}