Why AWStats doesn't consider a visitor with the combination of IP and UserAgent ?? I think this is the most logical way to diferentiate visitors as Webtrends appears to do. I want to change AWStats to do this but the code is a little complex to me and I have no clue. Can you help me on anything?

I want to migrate from Webtrends to AWStats but Webtrends give me 3 times the number of visitors. I tested with a smal log file and Webtrends does well, but AWStats not. The IPs are the same because of a NAT, but UserAgents are different. See the sample bellow.

172.16.48.20 - Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)
172.16.48.20 - Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 1.0.3705)
172.16.48.20 - Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0
172.16.48.20 - Mozilla/5.0 (Windows; U; Windows NT 5.1; rv:1.7.3) Gecko/20040913 Firefox/0.10

Webtrends correctly counts 4 diferent visitors, but AWStats only count 1 visitor, since the IP is the same.