open the settings.xml file with notepad or an other text editor
the file is @ this location:
amsn/script/skins/BlackCarbon/settings.xml
when you open the file add this to it
<login>
<Colors>
<loginfg>#d2d2d2</loginfg>
</Colors>
</login>
to make it easy look for the line <skin> and copy it underneath that line
restart amsn and normally the text would be white (works for me)