I use the following to send CTRL for the CAPS LOCK key, send ALT for the CTRL key, and send CAPS LOCK for the ALT key. CTRL is to the left of "A" where God intended it, ALT is below SHIFT, and the utterly useless CAPS LOCK key is safely tucked away where I have to break my wrist to hit it.
Windows Registry Editor Version 5.00
; The hex data is in five groups of four bytes:
; 00,00,00,00,\ header version (always 00000000)
; 00,00,00,00,\ header flags (always 00000000)
; 04,00,00,00,\ # of entries (3 in this case) plus a NULL terminator line.
; Entries are in 2-byte pairs: Key code to send & keyboard key to send it.
; Each entry is in "least significant byte, most significant byte" order,
; e.g. 0x1234 becomes `34,12`
; 1d,00,3a,00,\ Send LEFT CTRL (0x001d) code when user presses the CAPS LOCK key (0x003a)
; 38,00,1d,00,\ Send LEFT ALT (0x0038) code when user presses the LEFT CTRL key (0x001d)
; 3a,00,38,00,\ Send CAPS LOCK (0x003a) code when user presses the LEFT ALT key (0x0038)
; 00,00,00,00 NULL terminator