I could be wrong about this as i am no can bus guru, but i believe the third party can option is only to receive data. It was only after a recent upgrade that the ic7 (firmware 2.28.x) was given the ability to “master” a haltech pd16. I think you would need to enable haltech bus and include a pd16 then input the required receive info in the pmu16.
I would try importing the haltech canx file in the pmu software with the ic7 setup to haltech bus with pd16.