Logging errors to event viewer from custom workflow activity and invoking custom workflow from client application

Hi,

I have created a custom workflow activity and have deployed it to FIM and it is working as expected. I have below queries:

1. I want to log errors or information from my custom activity to event channels of FIM in the event viewer (not create my own channels in event viewer). Is it possible to do this? If yes, then how can we achieve this?

2. This custom workflow is part of one MPR and is triggered as part of any change in the user's phone number. Is is possible to invoke this workflow from a console application or any external application and return status to that calling application?

Thanks in advance for the help.