Set UserTask Bounday Event Timer expression on assignment

Hi,

I have to set timer at bounday event on userTask. When any processInstance arrives at any User Task i have to send escalation emails after certain time duration (e.g. after 2 days at an interval of 15 min) and will change assignee to immediate manager of assigned user. But these days and hours will be counted after execution arrives at particular user task and assignee is set for that task. How can we model BPMN for such process and set the timer values dynamically after assignment on userTask?

Any solution?

It’s not pretty but it would work: