I would recommend contacting the developer of the program. The problem you are experience is most likely due to the fact that the program itself was not designed to be able to make use of the APIs that Windows 8 uses for it's touch/pen inputs and would require the program's developer to release an updated version, or patch, for the program in order to tell it how to interpret the inputs. (While the OS knows what you're doing, the program doesn't know what the OS is saying you're telling it to do, if that makes more sense.)
Since you need to be able to use the right-click feature in the here-and-now my recommendation, while not ideal, is to pick up a wireless/bluetooth portable mouse - the small variety - that you can use in the interim as the right-click functionality will be universal. This information can be confirmed by the fact that the trackpad's right-click functionality does work in the program.
Sadly, this isn't something that Microsoft will be able to resolve as it's a program-side issue and not something wrong with the Windows operating system. I hope this information is useful.
-Llethander-