for (index = 0; index <= count; index++) {
        tmp = *av_fetch(val_arr,index,0);
        string = SvPVutf8(tmp,len);
        message->str[index] = savepvn(string,len);
}

##</code><code>##

int n = count;
char* p = &m.str;
while (n--)
{
  ....blah...
  *p++ = savepvn(string,len);
}