Data in callbacks and use of Glade

[Thames <thames get2net dk>]

Hi...
I'm a beginner in GTK+ programming, so i have a lot of questions :-)
But not to tire anyone, have cut them down to one:

1. I use Glade to design my interfaces. In a program I'm about to
design, there is two text entry's, a button an a tree.
What I want my program to do (this is just a sample program) is that
when i press the button the text from the two text entry's to be added
to the tree.
I know how to add a signals to the button, but I don't know how to add a
pointer to the two text entry's and the tree at the same time.
I can only make a pointer to one of them, not all together.
How do I do that??
I have tried some solutions, one was to make a structure and in that
structure add pointers to the two text entry's and the tree, and then
pass the structure in the "clicked" signal, but I couldn't make i work.

Thanks
Thames

(Sorry for all misspellings, but i am a dane :-)