Bug 119566 Support template items in page header/footer
Currently you can't create template report items inside a page header/footer. This should be fixed.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
assert getDefn( ).canExtend( );
			assert !( value instanceof ElementRefValue );
			if ( value == null || value instanceof DesignElement )
				setExtendsElement( (DesignElement) value );
			else
				setExtendsName( (String) value );
		}
		else
		{
			assert false;
		}
	}
	/**
	 * Sets the value of a property. The value must have already been validated,
	 * and must be of the correct type for the property. The property name must
	 * also be valid for this object. The name can represent a system or
	 * user-defined property. The value is set locally. If the value is null,
	 * then the property is "unset."
	 * <p>
	 * Part of: Property value system.
	 * 
	 * @param propName
	 *            The name of the property to set. Must be valid. Can be a
	 *            system-defined or user-defined property name.
	 * @param value
	 *            The value to set. Must be valid for the property.
	 */
	public void setProperty( String propName, Object value )
	{
		ElementPropertyDefn prop = getPropertyDefn( propName );