SendEmail activity does not work from custom SequenceActivities

The SendEmail activity works only when it has assigned the correlation token of the current workflow. When you add a SendEmail activityto a custom created sequence activity, it does not have access to the the parent workflow token and when you try assign a  different correlation token it throws following exception:
Correlation value has not been initialized on declaration [token]  for activity [sequenceActivity]
The workaround is simple just use the SPUtility.SendEmail wrapped in a CodeActivity.
Another solution is to create your own activity that would wrap the SPUtility.SendEmail.