Exchange free/busy replication between 2003 and 2010

Is there a way to replicate the free/busy data between Exchange servers using some tool other than the InterOrg Replication tool?  My problem is that we are migrating to a new Exchange 2010 setup, but we need to maintain our free/busy sync with a sister company which is still running Exchange 2003.  Microsoft informed me that the InterOrg Rep tool is not compatible with Exchange 2010.  The only workaround they had available was to install an Exchange 2003 server into our new Exchange 2010 org, and use that new 2003 server only as a public folder repository.  We could then use the InterOrg Rep tool to sync between our 2003 server and the sister company's 2003 server, and then use normal public folder replication between our 2003 and 2010 servers.

This certainly sounds like it would work, but it seems like a waste to have an Exchange 2003 server for no other reason than to essentially act as an InterOrg Replication tool translator machine.  That being the case, can anyone recommend a potential alternative?  Perhaps a 3rd party tool that will do free/busy replication and is compatible with Exchange 2010?
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NetAdSubsConnect With a Mentor Author Commented:
It turns out our sister company is unwilling to install any new software into their network, so that pretty much rules out any 3rd party solutions, such as the Quest migration tools or NetSec's GalSync tool (since those tools require the parties on both sides to install the tools).  So, we ended up going with option #2 I listed in my previous post.  We destroyed and rebuilt our AD and Exchange 2010 environment, but this time start with an Exchange 2003 server.  This will allow us to use the normal Interorg Replication tool from Microsoft, which our sister company is already using.
NetAdSubsAuthor Commented:
An update:  I just spoke with Microsoft again, and it turns out we actually cannot install an Exchange 2003 server into our existing 2010 environment.  The reason is that, since we currently only have 2010 servers in our environment, we have a "pure" 2010 environment.  This means no older versions of Exchange can be installed.  This TechNet article has the details on that: 

So, our only options are:

1)  Find some 3rd party method to sync free/busy info.

2)  Destroy our existing environment and start over from scratch, but this time starting with an Exchange 2003 server, then adding 2010 servers into the mix so we don't have a pure 2010 environment, but rather a mixed environment.

Obviously, option #2 is not ideal, since we'd be starting over and losing all of the substantial work we've done so far buidling up our new environment.

Quest Migration tool will be Handy for you
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