Hi :-)
Well, as it is said in the other tread you need a v37.300
kickstart rom for hard drive support in the A600.
Every rom older than that has NO hd support.
BTW, can you tell me : the version of your Workbench/kickstart rom, the exact references of your hard drive it will help me to try to solve your problem :-)
BTW II, unfortunately some Compaq branded hard drives are known to NOT work at all with the Amiga IDE interface.