MPS devices (Multi purpose Sensor) all use the same controller board. Because of that the Aquaero uses different bits of info from the mps control board to do different things. That is why when you look at the alarm configuration tab of the MPS page when connected via USB they all have Internal and external temp sensor, flow rate, fill level, speed signal, and pressure fields. A pressure sensor uses the same parts as a flow sensor but in a different housing.
When the device is connected via USB use the configuration tab to change it to a pressure sensor 500 device, give it a unique address and save the settings. It should then show up in Aquasuite as a fill sensor, and you can add the data to an overview page.
To have the fill level on the Aquaero display you need to go to go to Information pages / available screens and add a fill sensor to the list of screens your device displays.
If you still have problems then put up some screen shots so we can see what is happening.
Edit: Actually ... all that applies to the fill sensors but maybe not the pressure sensor you have. Sorry, got a bit confused. What do you want to do with the device? It may be that it needs to be connected via USB because the Aquaero doesn't really have a straight pressure sensor interface built in.