Light gun games in Demul, help a noob please?

Hi everyone,

So, I'm sorry for being such a total noob but I've Googled and can't find the answer to what should be a really basic question....

I want to play House of the Dead 2 and use my mouse to emulate the light-gun, how do I do this? If I select Light Gun in Maple Device Manager, Demul just doesn't read any of my inputs.

Thanks in advance.