Troubles to get started with SD240 Retrofit

Your HAL looks correct.
When you say "in the oszy" do you mean in the HAL oscilloscope , or on a physical one?

In the HAL oscilloscope try scoping both the index-enable signal and the hm2_7i80.0.encoder.00.input-index pin.

If index-enable is high then it should go low when the (short) input-index pulse is seen. 
The index-enable pin should go high as soon as the home switch trips. 
 

You can test the index-enable system by hand.

Open halshow (this is "show machine configuration" in Axis, in some other interfaces you may need to open a terminal and "halcmd loadusr halshow"

Add the x-index-enable signal to the Watch tab. I think you should see a button that allows you to set it.

Then rotate the motor by hand, and see if the index-enable signal ever goes false.

Hint, the colour scheme of halshow is eccentric. dark red = 0 / false and yellow = 1 / true

You can test the index-enable system by hand.

Open halshow (this is "show machine configuration" in Axis, in some other interfaces you may need to open a terminal and "halcmd loadusr halshow"

Add the x-index-enable signal to the Watch tab. I think you should see a button that allows you to set it.

Then rotate the motor by hand, and see if the index-enable signal ever goes false.

Hint, the colour scheme of halshow is eccentric. dark red = 0 / false and yellow = 1 / true