[TowerTalk] Mounting roof-top tower on tile/shake roof

[Michael Fox (K5MEF)]

I would like to mount a Glen Martin roof-top tower 
http://www.glenmartin.com/catalog/page14.html
on a Hardishake roof.  

(Hardishake is no longer made but it is a lightweight flat shake that sort
of resembles slate but is made of some composition of materials.)

Anyway, the point is, I can't simply sit the tower legs on it and bolt it
down like with composition shingles because it will crack the tiles/shakes.

So, I need to install some sort of mounting points that allow the tower to
sit on the mounting points and not put pressure on the tiles.  I'm not a
roofer, but I presume I'd need some sort of commercial product that
incorporates flashing to direct water around the mount point.

Has anyone done this?  And, if so, what commercial product did you use?

I've seen some commercial products for mounting satellite dishes, such as
CommDeck http://www.rstcenterprises.com/our_products/commdeck.phtml but I
don't know if that will fit the bill or not.

Any other ideas?

Thanks,
Michael K5MEF