scotopia - It looks like you figured it out manually but there are some details about how to programmatically create affiliate links from raw iTunes or App Store links.
iTunes & App Store Affiliate Tools - Advanced Affiliate Linking
In regards to DenVog's comment about the different items available in different stores this is absolutely correct. Even though an item may be the "same" thing it may have a different ID and therefore the link will be different. This obviously makes things a little more challenging when dealing with an international audience.
And finally in regards to creating the link before it's available the ID is the only thing that is important. I think you can have whatever you want as the title and it won't matter.
I hope that helps.
Let me know if you want to try out my service that does the geo-targeting, translating and affiliate encoding on the fly for iTunes and App Store links.
