Hi Dinh,
First, this post is 3 years old! If you need the related feature, use the last Store module 03.00.00 available at
Codeplex! The ADDQUANTITY token have been added from a looonnnggg time! :-) Moreover, you should download and read the Templating Guide because you can change a lot of things WITHOUT using the source version!
If you want to work with the source version, please read
this post. You should
NEVER extract the source code by hand!!! To save plentry of times,
PLEASE PLEASE PLEASE follow my advices from this post!!! It seems you develop using the WSP model, but some modules like the Store use the WAP model. This is why it's REALLY important than you follow my advices. If you have never used a WAP project, please read
this article at MSDN. In the ASP.NET context WAP is NOT related to mobile development!
If you have more questions, please open a new thread. :-)
Gilles