Riftsaw is based on the Apache ODE BPEL engine, which does not support this type of adapter. So currently it is purely web service orchestration.
For the next version of Riftsaw (version 3) we are embedding inside the Switchyard ESB, which can provide a wider range of integration possibilities and adapters - although the current first milestone of version 3 still relies on a WSDL interface between components.
Best thing would be to raise a jira with your requirements and we can consider how best to add this functionality.
When RiftSaw 3.0 will be released?
Riftsaw 3 is currently at milestone 4, and integrated into switchyard 0.7.0.Final (http://www.jboss.org/switchyard.html). BPEL quickstarts are bundled as part of the SwitchYard AS standalone distribution.
The final version of Riftsaw 3.0 will coincide with the release of SwitchYard 1.0.0.Final - but a date for that hasn't been decided yet. You may want to check with the SwitchYard team to find out whether they have more information on dates.