Microsoft Indexing Service help

[U_X_U]

Hello, all,

I've made a small VC++ routine for a project to search its data archive. I've used Microsoft's Indexing Service at my boss' recommendation. Now the client needs full documentation on Indexing Service's limitations (like, for example, can it support searching on 5,000,000 documents). I've spent all day today searching for resources on Indexing Service but nobody specifies what it can do!
Do you happen to know where I find such specifications?

Thank you...

[Waldo2k2]

first hit on msdn
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/indexsrv/html/ixufilt_0y91.asp