Using Exmerge on Exchange 5.5 with mailbixes > 2Gb

I have an Exchange 5.5 server (Windows 2000, SP4) from which I want to extract some mailboxes, a few of which are > 2Gb in size. I have copied the latest version of Exmerge (ver 6.5.7529.0) into the program files\exchsrvr\bin folder on the Exchange server as I know the version of exmerge that comes with 5.5 cannot handle PST files greater than 2Gb but later versions can and are backward compatible. I ran exmerge on a couple of mailboxes which were only around 1Gb in size, producing PST files <2Gb. So far so good, but when I tried to exmerge a mailbox which was would produce a PST file > 2Gb Exmerge create the files upto the 2Gb size and then just sat there not processing any more messages, but not giving any error messages.

I then tried installed the Server 2003 admin tool pak on an XP laptop, installed Exchange 2003 tool and the latest version of the service pack for Exchange 2003, made sure I have the latest version of exmerge in the program files\exchsrvr\bin folder on the laptop and tried again. same result, exmerge got as far as creating a file of 2Gb, then just sat there doiong nothing.

Should the above work ?