Here are the RHESSI visibility modules and a sample save file.  
As you can see, the current versions are quite primitive and very 
much a work in progress, so that they should not be posted to ssw.  
It is certain that the format of the visibility output will 
evolve over the next few weeks so there is no guarantee of future 
compatibility.

At present, the basic starting point is vis_test, which can be 
edited to correspond to whatever event/energy range you choose.  
It is just a shell that calls hsi_visibility_analysis which in 
turn calls various functional modules and saves the resulting
visibilities.

As a timesaver, having generated (and saved) the visibilities 
once, you can (optionally) RESTORE the save file containing 
the structure with the visibilities, and then call 
hsi_vis_display, hsi_vis_avg_size, hsi_vis_consistency_check 
and/or hsi_size_vs_pa directly with the visibility structure 
that was saved.  

vismar25.dat is a sample save file with the visibility structure.