VKB-SIM

I want to use a axis as axis in normal function, but it must act as a button when I active shift function. I am not getting how to get it. Thanks.

In what axis position? See axis to buttons.

For now, it doesn't care the position, I just want to convert an axis into a button when Shift is active.

For example, in DCS Blackshark there are "Wheel Brake" (axis) and "Parking Brake" (button) functions.
I want to use the MCG paddle as "wheel brake" to slow down and stop the helicopter, and after that to activate "parking brakes" using the same paddle but now acting as a button so, to get a double function, I have to configure a button as Shift. Now, how to convert the paddle in a button only while I am pressing Shift, and to act as an axis again when I release the Shift button?.

You can also use the brake button without Shift. Use the slider to adjust the zone in which the button will start to work. Or is it not suitable?

This method (A2B only) can be dangerous. If you accidental move axis to extreme position parking brakes will be on. While velocity is not zero. I think joaquinbaeza is right with separate button to activate parking brake.
Thus begin.
!Note. I have not MCG handy so my example is based on other controller. Your axes and button numbers will differ.
Axis2button function output is button. Button-modifier will convert it to another one. Save one line. Boolean Comparator1 will replace A2B.
Open Profile - Boolean tab. Click first empty slot. Select Comparator1. Layer=1(axis #) (remember, you will assign your. As I remember MCG brake lever is #3).
Treshold = 96 or how near the bound you want to register brake chock. Output = Free! No line number is occupied. Comparator output only.

Click next slot and select 2AND function. Output will be registered if BOTH inputs are ON. 1st input layer = Physical button 15 - our modifier (Remember.....)). 2nd input is Boolean 1, Free output of comparator. Output = Physical button. Any free. 40 for me.

No need to register modifier press as button. Profile - Buttons - Physical layer tab. Click line 15 and select No function.

That's almost all. All if in DCS button for parking brake must NOT be pressed all the time, press and forget.
If it must be pressed all breaking time, than make button 40 Button Alt (similar to CapsLock). Click line 40 and select Buttons - ButAlt. Def. State = OFF.

Press SET. See result.

Sorry! I have forgotten about MCG break lever special function! And solved problem in general terms))). Thanks to Ron! You can combine Ron's method with my.