Never mind, I found it:

[ServiceEGS]
CachedExchangeConfigFlags=0x00000100

[Exchange Global Section]
CachedExchangeConfigFlags=PT_LONG,0x6629

"Drew" wrote:

I've almost got my prf file ready for deployment. One last option I need to
enable is "Use Cached Exchange Mode" on page 15 of the prf whitepaper is has
a screen shot of the option I need to check, but makes reference to "use
local copy of mailbox". Is this simply a typeo? If not what is the
information I need to modify to check that box?