Threat model of a Mobile app

There is some pushback from mobile app developers that the creation of a threat model in IRIUS RISK does not work. My question: Doe anybody have any experience and or guidance which could help us?

Are you looking for just best practices in getting mobile app developers to create threat models in IriusRisk or is the tool having technical issues that is preventing them?

I am looking for best practices and maybe even an example. Thanks