How to define specific value for BAD?

[Daniel Müller <mueller@xxxxxxxxxxxxxxxx>]

Dear Ferret-Users

I was just wondering how to define a value as bad flag (0 is desired)
when saving a variable defined by "let my_variable=..." to a NetCDF-File
using "save/file=test.cdf my_variable".
Right now when I look at the created file using ncdump i see
"missing_value = -9.96921e+36f"  and  "missing_value = -9.96921e+36f".
How to change this to 0 (Zero) within ferret?
I already tried "set data/bad=0 ..." and "set variable/bad=0
my_variable" which didn't have the desired effect.  

Can anybody give me a hint?

Regards

Daniel