Filtering Log Problems

I am currently having problems with Custom Logs under Apache 2.0.49 on
Windows XP.

I am trying to achieve one of the following :

1) Ignore all requests where the status code is 401

or

2) Capture only requests that have a User Name with them

I am trying to use the SetEnv If function to get this to work. I cant
see that there is a variable that I can test for the status code, so I
have looked at the capturing of the user name. I am using the
following in my httpd.conf file :

SetEnvIfNoCase Remote_User "[a-z]" LogHit

This is not picking up any requests, even if they have a user name
associated with them. I know that requests are logged as I set LogHit
for other files and they appear in the log file.

Dose any one have any pointers that might help me?

Many thanks in advance.

Alistair