Resoldering Ultrasonic Sensor Heads

Hi Arduino community!

I am working on a water level measurement project and I am using the available Ultrasonic Sensor module (http://store.arduino.cc/product/SEN136B5B). However, I will need to use it outdoors and obviously the mesh sensor heads don't really tolerate water being splashed on them. So I was looking for a waterproof solution and found these 40Khz waterproof sensors. Given that the sensor frequency is the same for both, would the module work properly after I solder the waterproof sensors on the non-waterproof module?

What variables are there that I have overlooked?

Any help would be greatly appreciated!

-Marek

Sensitivity, impedance.