Mikrotik Web Proxy - Hide Internal IP Address

Hello.
We try to use Web proxy to filter some URL.
But Mikrotik web Proxy disclouse some data in special my internal IP address.
You can verify this via http://proxy-list.org/ru/show-my-ip.php

IP Прокси: 88.88.88.88 [Transparent proxy]
Код страны: unknown Имя страны: unknown

IP Прокси: 192.168.0.34
Код страны: unknown Имя страны: unknown

Accept: text/html,application/xhtml+xml,application/x ml;q=0.9,/;q=0.8
Connection:
Language: en-us,en;q=0.5
Referer: (none)
Protocol: HTTP/1.1
Encoding: gzip, deflate
Port: 39800
Browser: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:10.0) Gecko/20100101 Firefox/10.0

In 3proxy this can be hidden via key
3proxy -a

Can you please add an option to hide my internal IP.

Thank you.

It would be good but maybe not possible. See http://forum.mikrotik.com/t/how-can-i-hide-proxy-headers/29152/1