After thousands of re-writing this code, I've got finally results :
Code:
@ DEVICE PIC12F675, INTRC_OSC_NOCLKOUT, wdt_off, pwrt_off, mclr_off, bod_off
DEFINE OSC 4

CMCON = 7               ' Comparators disabled
ANSEL = 0               ' A/D disabled

@ #define IRTX GPIO     ; Define port to use for IR out
@ #define PIN 1         ; Define port pin for IR out


 Puls_a         CON 112  ' 112 x 26uS = 2912 mS ( pulse with carrier ON)

InterPulse  CON 2800 ' 2.80mS (delay between pulses with carrier OFF)

Puls_b        CON 28   ' 28 x 26uS = 728 uS   ( pulse with carrier ON)





X        VAR BYTE ' Data bit loop counter & bit index pointer
Duration VAR BYTE ' Duration of button press
Loops    VAR BYTE ' Loop count
Cycles   VAR BYTE BANK0 SYSTEM' Number of carrier cycles to generate


trisio=%11111101
option_reg.7=0
wpu	=%11111101

but  var gpio.5

                        

    GOTO Main       ' Jump over pulse routine to Main
    
Pulse:              ' Generate "Cycles" number of 40kHz pulses
ASM                 ; Keep this routine in code page 1, and jump over to Main
   	BSF	IRTX,PIN		      ; 1 MAKE IR HIGH 35% Duty cycle = 9 uS
	GOTO	$+1
	GOTO	$+1
	GOTO	$+1
	GOTO	$+1
	BCF	IRTX,PIN		      ; 1 MAKE IR LOW 17 uS
	GOTO	$+1
	GOTO	$+1
	GOTO	$+1
	GOTO	$+1
	GOTO	$+1
	GOTO	$+1
	DECFSZ	Cycles,F	
	GOTO	_Pulse	      ; 2    26 uS
ENDASM
   return           ' Return to caller    
    
Main:

Duration = 2    ' Send it twice

IF BUT=0 THEN    
For Duration = 1 to 2
        Cycles = Synch         ' carrier on
        Call Puls_a             ' Send pulse

        PAUSEUS InterPulse    ' Pause (carrier off)

        Cycles = Logic0        ' carrier on
        Call Puls_b             ' Send pulse

		Pauseus 50000
		Pauseus 50000
Next Duration

ENDIF    
    GOTO Main                  ' Return for more

    END
This is command for Volume Up only ; instead 102 cycles * 26 uS = 2650 uS, I put 112 * 26 = 2912, etc. So, the lenght of one pulse is 23.5 uS ?! Maybe with this PIC... Anyway, it's good to see that working, after hard work... Thank You all for support; every advice it's further wellcome !