You can't change the level of the message itself so you have to continue to log at the Informational level if you want any of those messages. However, you can turn off individual messages with the "no logging message NNNNNN" command, where "NNNNNN" is the message number. While it may look like you'd have to turn off a huge number of messages to only get the ones you want, the reality is that there are probably only a few (a dozen or so) that you're getting a lot of, so it's not too bad. The System Message section of the PIX docs list all the messages by severity level, so you can go through them there, or you can just look in your logs and turn off the ones you no longer want to see. Unfortunately, there's no way to turn on individual messages - you have to log the entire severity level and turn off the ones you don't want.
HTH
