Hi Philip,
SAM does not explicitly model hybrid CSP-biomass systems, but you could use the Combine Systems macro to model the systems separately but combine the revenue for the financial model.
Here are some instructions for combining a Photovoltiac and CSP system using that technique:
sam.nrel.gov/forum/forum-general/2247-hybrid-csp-pv-generation.html#6742
Best regards,
Paul.