Has anyone done a replacement for sendkeys using either SendMessage or Postmessage and the WM_KEY* or WM_CHAR messages?

If so - how do you create the lParam component of the message?

The documentation says:
Bits 0-15 is the number of repetitions
Bits 16-23 is the OEM scan code of the char
Bit 24 is set if it is an extended key
Bit 29 is set if ALT is pressed
Bit 30 is set if the key is already down
Bit 31 is set on key up, zero on key press
Also - do you send 2 messages - one key down and one up for each character?

Thanks in advance,
Duncan