Your translation program fails us a bit here and it is difficult to follow the question, but let me try...

1st question appears to be asking if an additional pressure sensor to the one in the Aqualis XT can be used?
I believe so, with the stipulation that only 4 MPS devices can be used with one aquaero, and you may need to set the device address in aquasuite.

2nd questions appears to be asking if the fill level sensor with the aqualis XT would continue to function properly?
Yes, as long as no more than 4 MPS devices are connected to an aquaero.

If I misinterpreted the questions, please restate them.

Quoted from "dopax007"

Tkanks and sorry for my bad english...........the Aqualis XT reservoir comes wit a pressure equalization menbrane that , if I'm not mistaken , it's necessary for the proper functioning of the fill level sensor ............. my question was if I could or not to use a different pressure valve ( the koolance pressure valve , for example ) and , if so , whether this would affect the proper functioning of the fill level sensor

No. The Aquacomp is a very free flowing air valve that always keeps the pressure in the res at the same as atmosperic. If it didn't the fill level sensor would change without the actual fill level changing because it works by sensing pressure.
The Koolance model is a saftey valve that only trips at a certain pressure above atmospheric. Other models like the Bitspower are purely manual models and fill levels would be all over the place unless you regularly manually cycled it.

Of the ones I know of only the Aquacomp will maintain proper fill level sensor function.