Do you mean DS1232?
If yes, how do you feed the watchdog?

10MHz is a quite nonstandard crystal frequency, but you should autobaud auite safely even at 9600Baud - the 89C51RD2's bootloader has a similar autobaud procedure as the P89V51RD2 - and I'd bet it is the same with the RC2 - you can check out the crystal vs. baudrate error at http://www.efton.sk/t0t1/autobaud_error.htm (and .xls).

But you can also check more in (hyper)terminal than the simple "U" autobaud - after successful autobaud it should echo all the characters you type; also typing :020000050000F9 and similar commands should echo and append the IDs of the chip. In fact, you can completely avoid FlashMagic usage and perform the programming entirely in a terminal, typing in the "hex record" for appropriate block erasing (or having it prepared in a separate file and sending that file); then setting a inter-line delay of cca 200ms and sending out the hexfile you intend to program. But beware: check that the boot vector remains unaltered (or reprogram it) otherwise you can run into troubles ("bootvector loss syndrome").

Finally, you should perhaps post your question at the FlashMagic Forum, http://www.esacademy.com/software/flashmagic/forum .
[Edit] sorry now I see you have already there...

Jan Waclawek