[Greenbuilding] Clamp Solar Collectors to Standing Seam Roofs

[Lawrence Lile]

I have been agonizing about how to attach my solar water heater collectors to a standing seam roof.  Who needs penetrations in a standing seam roof?  These guys make a clamp that clamps things onto the ribs.  
 
 
 
http://www.s-5solutions.com/html/Hardware/
 
 
I do wonder how much uplift a standing seam roof can handle - would a solar collector present more of an uplift force in a high wind than the roof itself?  I suppose there would at least be a sideways force that the roof would not normally be subject to.  Anyone have any thoughts on this?  How have you attached solar collectors to standing seam roofs, and was it successful? 
 
--Lawrence