Here is what i have found after spending 3 days doing research:
Download version 7th on the web and extract it out.
1. copy everything onto the root of the memory card (MicroSD in this case for R4), well, you don't need readme.txt or wifi.nds if you have a commercials game that can setup the wifi.
Patch your .nds file if the card doesn't have auto patching on. R4 in this case is unnecessary. (version 1.14)
2. edit your config file..
- DO NOT ADD ANYTHING NEW OTHER THAN THE ORIGINAL FORMAT, for sip.voipbuster.com
--domain sip.voipbuster.com
--username yourusername
--password yourpassword
... whatever here i don't remember but that's all you need. You people add the --contact but it isn't necessary that i've found.
3. Now it should works.
-- And if you are using a router, open ports 5060 but i don't know if this is necessary because we don't have the --contact in the config file and we are not having any kind of connection to our local computer ip. So, try this on your own.
========================PROBLEMS=================
1. Stuck at the splash screen and nothing happened
- this is because it is trying to connect to your wifi connection. It will stuck forever until it is connected to the wifi. To fix this, well, i am using Soft AP for Nintendo Wifi Adapter. You have to set the Network Authentication to Open, WEP key to manual, Hide SSID (this is unnecessary, it doesn't matter. I hid mine and it still works)
2. Invalid URL: username@(null) (version 6th) will say this but in version 7th, it still say something similar like call.c invalid...
They are the same error actually. To solve this, GO back to the config file and again.. don't add anything else other than the suggested parameters.. Thanks Samuel!!!
3. If you still stuck at the splash screen, try to Unhide SSID, No WEP key, Network Authentication = Open, AGAIN this most important thing, No Firewall (Windows Firewall doesn't block this, if you're using ESET Smart Security - Only solution, uninstall it)