Hi lpickard

To summarise:


There is no way to increase the number of messages that BES will pre-populate to a device (well, no supported way, and a hack could kill BES)

There is no way to increase the pre-population even if your boss' account had NOT been deleted from BES. BES sends out the pre-populated volume as per the BES settings. If BES is set at max, it doesn't matter if your user is a first time BB config or actually swapping devices - max OTA pre-population is exactly what it says.

The only way to transfer message history is to backup the old device, restore messages onto the new device, then EA the new device

There is no way to get the BB handheld to "retrieve" messages from the mailfile that aren't on the BB (i.e. a BB can "get more" on a partially downloaded message, but can't go and find messages from 8 months ago)

The other way round it is to forward a lot of messages, but you have ruled this out

Have no idea regarding Exmerge, sorry

Sorry not the answers you wanted, but that's the way it is