It works. Here is the procedure:
1. create a MS-DOS boot disk on your PC. Use a DD disk (720K) to be safe.
2. create an image file from the disk. Use a program like WinImage for that. The image must be exactly 720KB in size, no header and no compression.
3. start WinUAE and boot AmigaOS.
4. press F12, go to the floppies tab and create a custom floppy.
5. write the MS-DOS image to the floppy. Use a program like TSGui for that.
6. start PCTask and boot from the custom floppy ADF.
Bye,
Thomas