Use the expression language when defining the wizard label (window title).
<wizard>
<label>new ${ Type } file</label>
</wizard>
Use the expression language when defining the wizard page label and description.
Example
<wizard>
<page>
<label>${ Type } file</label>
<description>Create ${ Type == "XML" ? "an" : "a" } ${Type} file.</description>
</page>
</wizard>