One of the support engineers in a company has managed to bring on a huge client, one that will completely change the valuation of the company. What is the standard compensation that you think he deserves?
there are probably many right answer to this...
in my opinion, i think the "fair" thing to do is to compensate the support engineer in just the same way as you would your top sales person if they had bagged the client and smashed their targets. So if that's a % of margin, then thats what the support engineer should get. don't short change it.
the other thing that i would do is "praise" this like crazy ... let it be known through out every corner that the shift in the needle can happen from the most unlikely of places, and that where ever it comes from it will be rewarded fairly and recognised heavily.
hope that helps... :-)