UWL task approval with confirmation popup

Hello:

I'm trying to implement a confirmation popup in a decision task, and I've seen that it can be made by using a ConfirmationDescriptions tag as a child of Action tag.

Searching for more info in help.sap.com, I've found that it works like Description tag, but I was not able to make it work on my custom DTD due to XML validation.

Please, can anyone provide a working example of a UWL DTD using the tag ConfirmationDescriptions as a child of Action tag.

I'm working with SAP Nw EP 7.31.

Thanks in advance for your kind advice.

Best regards.

Rafael López.