[Chimera-users] Problem with useSymmetry option in vop

I'm trying to use the "vop cover" command to extend an electron density map (read in in ccp4 format) to cover an atomic model. The following command: vop cover #0 atomBox #1:1-20 pad 2.0 useSymmetry true results in the error: Keyword 'useSymmetry' doesn't match any known keywords. Can you see what I am doing wrong? Background: I know that the manual says that "true" is the default value for useSymmetry, but the bold font in the usage statement suggests that "false" might actually be the default. If I leave out the "useSymmetry" keyword, the results look like only unit cell periodicity is being used (i.e. looks like useSymmetry is set to "false"). This is why I am trying the above command. ...thanks!....dave case