When I get my nim server started up (I am 5 hour plane trip from my nim server, now offline) I'll take a look. However, you might just try using:
smitty nim
... Administer ...
Manage Resources->Define Resources

In the dialog that is there linux_source - whatever it's name may be - is one of the resource types that can be defined. You will recognize it! and then press ESC-6 (Escape 6 - two key presses) to see the command it makes.

or, from the command line just type:

nim -o define

and read carefully the error/syntax message presented.

good luck - do update with the correct command!