If you choose to define help text for properties directly in the extension's XML file, you use the element <help> in the property definitions. For example, assume that a step has a property named geometryfile. You might define custom help for this property in the element <help> as follows:

<property name="geometryfile" caption="Geometry file" control="fileopen" default="">
		  <help>Select a geometry source file to import. Note the geometry should contain the flow volume in addition to the structure.</help>
      <callbacks>
          <isvisible>isVisibleGeometryFile</isvisible>
          <isvalid>isValidGeometryFile</isvalid>              
      </callbacks>                
 </property>