the kit communicates with the terminal from windows very well but using the hardware the kit has, but my programs can't becasue it does not have a maxim or a similar ic for rs-232, the signals comes as I already told you
If it "communicates with the terminal from windows very well" it does have a MAX232(equivalent)

from the manual:
Supports 2 Full-Duplex RS-232 serial channels. The primary port is taken from the CPU's UART and includes activity LEDs. The secondary port is software driven. The RS-232 driver has a low power shutdown feature that can be controlled by an on-board jumper and through software. The CMOS/TTL signals are available for using external RS-422 or RS-485 transceivers.

I wish there was a schematic. Anyhow I read that a "RS-232 driver" (read MAX232 equivalent) is there but RxD and TxD go to pins as well.

Read the manual for your thang and find the RS-232 signals, NOT Rxd and Txd. Using the pins used to "communicates with the terminal from windows" and you will be fine.

Erik