Trying to find a way to mange workflow rules. Mainly looking for programatically activate a worflow rules and add new outbound message action into a workflow rules.

While we are currently using REST api to interact with Salesfoce for data (e.g lead, account etc ...), REST api doesn`t seems to have a way to manage workflow rules, and only metadat api can manage workflow rules.

My question is, if we already have the access token from REST API, can we use it on Metadata API calls (SOAP api i beleve)