Nap and sleep commands

[FinchPJ]

Since our production circuit board has been professionally produced, there is not room for an extra Xtal and caps to drive TMR1 so I am trying to get the WDT to do the wake from sleep but with only partial success. In particular it doesnt seem to matter what I put as a postscaler value the WDT seems to cycle at a fixed period of around 578 mSec (suspiciously similar to Nap 5 frequency!). I am setting CONFIG2H by using this instead of the corresponding (commented out) line in 18F4550.INC:

asm
       __CONFIG    _CONFIG2H, _WDT_OFF_2H & _WDTPS_256_2H
;must comment out in 18F4550.INC, or change there, else duplicate error
endasm

and then:

            i = 0
lowpower:   lcdout $FE, $02, "WDT ", hex2 i, 
            i = i + 1
            ' Do all the other stuff here (read ADC, store to Mem) 
            clearwdt
            WDTCON = 1       'SWDTEN
'           OSCCON.7 = 0     'Clear IDLEN - switch to SLEEP 
            OSCCON.7 = 1     'Set IDLEN - switch to SEC_IDLE
@           SLEEP 
@           NOP  
            WDTCON = 0    ' WDT off
            goto lowpower

and i increments 128 in 74 secs (period = 578mSec), but different values of _WDTPS_1024_2H etc. make no difference. What am I missing here? It makes no difference whether I make the CPU sleep or idle (except to the current consumption 3 or 15 mA - most of the 3 lost in the 9v voltage regulator).
DEFINE NO_CLRWDT 1 makes no difference and the CLEARWDT also seems to make no difference!

I would like to have the ability to control the frequency as expected and am thinking I can sleep for most of the 1 second I want and fine tune with another timer while awake - PAUSE would be the simplest. Any ideas gratefully received!

Peter

PS It just occurs to me that I am using a Bootloader - could this mean that the Postscaler is set by the bootloader and not changed by my program - if so can I do anything to change this ??edit the bootloader somehow.