Thanks for your feedback Geo !!
I could be wrong, but from first Vapors (2006) to the last ones (2008), the needed mast is moving from hard top to a constant curve bending. This datas can be checked at:
Ignition 2007 are "constant curve" mast, compared with the 2006 and previous.
For this reason seems possible use other mast brands than Gaastra on Vapors.