geometry H 0 0 0 H 0 1 0 O 1 0 0 end cosmo radius 1.1 1.1 1.8 end
cosmo end set cosmo:map custom.par
where custom.par looks like this:
The downside to the first example is that it's a PITA to use -- you need to enter each vdw radius in the order you are listing the atoms in the geometry section. It means that for a 50 atom geometry you need to enter 50 values, even if all 50 atoms are the same element.H 1.1 O 1.8
The downside with the second example is that you need to first create the run folder, put cosmo.par there and first then can you submit.
An easier approach is to create the custom.par on the fly using task shell:
task shell "echo -e 'H 1.1 \n O 1.8' > mycosmopars.par" cosmo end set cosmo:map mycosmopars.par