Drop Down on the Task Page of an Activity

Hi ,

I have a requirement:-

In a workflow for a particular activity , when a user recieves the task , user should see two attributes 1. Company 2. Country in the task page.

Also the input for the attributes should ONLY be a drop down list.

In the Workflow template , i have created two variables in the activity of type name : wt.org.WTUser to achieve the drop down but this only gives the names of users in the Windchill system in the drop down list.

Please suggest.  Please refer the screenshot attached.

Thanks

Ishaan