"Keil clearly says that array for bit is not allowed"

So there you have it!

'C' (anybody's 'C') is not good at addressing individual bits :-(

Note that Keil does give you bit-addressable objects - but not indexable, like an array.

If you really need to do this, assembler is probably your best bet: write yourself some bit-handling routines in assembler, and call them from your 'C'