Can't understand OpenIAB skus

I'm having a terrible time figuring out what OpenIAB wants me to use for skus. Especially for iOS, because none of their examples give the format that I am used to. Let's say that I give my product an Id of "com.mycompany.mygame.product1" and I use this across all of the stores for consistency.

Would I use:

 const string SKU_PRODUCT1 = "com.mycompany.mygame.product1";

to define it, or would I use

 const string SKU_PRODUCT1 = "product1";

and trust it to figure out the rest for the Android stores? And when it comes time to map that sku for iOS, which value would I set for the mapping to SKU_PRODUCT1? It seems logical to use the full reverse domain name product ID, but again, I can find no samples anywhere that use this format. So basically, I have no idea what to set the SKU string to, or what to set the mapping to. Any help would be appreciated.