I have just been talking to the guy's at Protek and they have told me the OP was looking for a battery charger for the electronic trigger. Looking at pictures of the battery pack it is a 5 cell battery. This means 1.2V x5 =6.0V. If the battery has not been charged for along time the chances are it will need replacing. Also be careful about the polarity of the charger as it might damage the electronic and the battery if connected wrongly.

I have also been asked to say that Protek have lots of walther spares just not the ones the OP was looking for. If you can tell them the walther 7 digit part number they can look up and see if they have them.