well, I'll describe it with other words.

e.g. My server has these Ips (they are not real):

90.90.90.90
90.90.90.91
90.90.90.92

So 3 Ip's Right? I want to download google.com page it has A record
209.85.171.100, so httrack can use ip 192.90.90.90 to make outgoing
connection, or he can use 192.90.90.91 or 192.90.90.92. Right? So guys on
google side, will see in web server logs one of these 3 ips. So how to set me,
what IP must to use HTTRACK for initial outgoing connections to remote host.

If you are useing CURL e.g. you can use this option: 
--interface <name>

Perform an operation using a specified interface. You can enter interface
name, IP address or host name. An example could look like:

 curl --interface eth0:1 <http://www.netscape.com/>

If this option is used several times, the last one will be used. 

If you are useing WGET you can use this option: wget --bind 90.90.90.90
<http://www.google.com>