Maximum messages processed per hour ?

Hi Experts,

I read a XI doc on Sizing SAP XI (ref. Sizing SAP

Exchange Infrastructure 3.0 - Version 1.1 - July 2004)

Examples are given with maximum of 108,000 message processed per hours : Is - it an unbreakable limit ?

A client wants to integrate each quarter about 5,000,000 documents per day during a long week.

Does XI can support such huge numbers of simple messages (no BPM, simple mapping, file-to-file scenario) ?.

Thanks a lot for your response.

Etienne