DDNS problem (inadyn)

I am having a problem with my internet connection (ISP).

Dreambox Inadyn (DDNS client) is not updating to my correct external ip. Its updated to a wrong ip.

My setup
Dreambox 500 >Router > Internet...

I tried to check my external dynamic address via the website
"http://checkip.dyndns.org/" & via "dyndns updater client" for windows both pointing to wrong ip.

My ISP is filtering web traffic through a proxy... that might be the reason

If I point my browser to [Only Registered Users Can See LinksClick Here To Register] it shows my correct external ip.


So is it possible to modify the dreambox inadyn client or script to use this web address "http://checkip.dyndns.com:8245/" to check dynamic ip instead of its default address "http://checkip.dyndns.com/" ?

Looking forward for any solution

Thanks in adavnce...