Hi Marcelo,
The first place I would look to see what happened with these missing Invoices is the Resolve Conflicts section in Method, found under QuickBooks->Resolve Conflicts. If for any reason you have a record that doesn't seem to have synced from one account to another, you more then likely have a conflict that will show up here. When you go to this tab, you will see a few different options/suggestions on how to resolve these conflicts so that it will sync.
You will see at the top of this screen a list of all your options to resolve the conflict, read the definitions and decide which would be best for your specific conflict. We have a whole section on Conflicts in our Help Center, for more info check out this link.
Please let me know if this helped, and that your two Invoices in question are in fact in your conflcts area. One other item to keep in mind, is the "RecordID" given in the conflicts area is NOT the same as your transaction RefNumber (which you provided in your first post), however provided the conflict has additional "Details", you can click on the Details->More Info.. link on this conflict, and you will see more info inside here, including "RefNumber".
-Ben