Hello Starbish,
you basically have to call SetNativeString() after you set the string to write the string buffer back for the caller.
There is an example in the wiki:
http://wiki.alliedmods.net/Creating_...pting)#Strings
The function FormatNativeString is a formatter function with printf syntax, that parses %s, %d formatters from variable arguments, but to change the string buffer you basically don't need it, except you want to have variable argument formatting support.
It's
described in the API Doc.