Deploying Access 2007 Runtime-Based Solutions

I have created an application using Access runtime and it works find. Now,
how do I upgrade the frontend? If I use the same product code or the same
upgrade code it tells me I have to remove the old one first before
re-installing. If I give it a new Product Code it installs the upgrade but I
end up with two entries in the Add/Remove programs list. If I use that
approach I will end up with potentially dozens of extra entries every time I
send out an upgrade. Can anyone tell me how I deploy an upgrade to the front
end? (see http://msdn.microsoft.com/en-au/library/bb501030.aspx)
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Cheers
Rob