上次的函数有误，这次的才正确支持中文。

'把普通字符串转成二进制字符串
Function str2bin(varstr)
   str2bin=""
   For i=1 To Len(varstr)
       varchar=mid(varstr,i,1)
       varasc = Asc(varchar)
       If varasc<0 Then
          varasc = varasc + 65535
       End If
       If varasc>255 Then
          varlow = Left(Hex(Asc(varchar)),2)
          varhigh = right(Hex(Asc(varchar)),2)
          str2bin = str2bin & chrB("&H" & varlow) & chrB("&H" & varhigh)
       Else
          str2bin = str2bin & chrB(Asc(varchar))
       End If
Next
End Function