Stylus won't click

Hi all,

today I purchased a stylus that's compatible for iPad and iphone..

It works perfectly on these devices, but somehow when I try to use it on trackpad of my macbook pro.....the cursor moves perfect except it won't perform the function of a "click"...

All it ends up doing is just moving the cursor which won't let me draw anything because it doesn't "click"...

I need help!!!

Updates:

Now , somehow it worked but there is a catch..

Under CS4 it will only start to draw lines when I click twice on the trackpad.

Meaning whenever I lifted the stylus over, I have to click two to draw something again.

Now, can you imagine what is it like to write a sentence with that setting//

Some Mac expert help me out..!!