Hey Simon,
What you want to do is possible & will work, have a look at this link:
http://www.caldigit.com/faq.asp#ChangeProjectS2VR
Please contact sales@caldigit.com for the spare populated modules for the S2VRDuo that you have & we'll square you away there.
Jon Schilling | Director of Business Development
CalDigit Inc
phone 714-572-9889 X234
fax 714-572-9881
web www.caldigit.com
office 1941 Miraloma Ave. #B Placentia, CA 92870