Hi!
Yes you can use any standard ide unit as a secondary drive, but probabply u need a 44pin to 40 pin adapter. However keep on mind that you probably can't write dvd disc with the internal ide port of a1200. Its simply lack of speed.
I have the same problem, so that's why i change to scsi. It has dma so don't use cpu, and about 10MB/sec transfer rate.