John Evdemon (Microsoft Architect) notes in a recent forums post:
Regarding WF, the underlying XML representation is XAML. Why did we choose XAML instead of BPEL or some other standard? Simple – XAML enables us to avoid the constraints imposed by a focusing on a single standard (e.g. BPEL lacks human workflow and sub-processes). WF is capable of supporting multiple standards
- A BPEL 1.1 import/export tool is currently being tested and will be released later this year.
- We are in talks with partners to add BPMN modeling for WF
- I am aware of a couple of projects looking at XPDL and BPSS for WF
- The custom loader (I believe it becomes available in Beta 2.1) enables us to directly transform a BP standard to an executable representation, possibly enabling support for executable BPEL.