Not sure how you were doing it before or what version you're using but in CS6:
1 - select the text to which you want to apply a pattern
2 - in properties toolbar, select the color option.
3 - at the bottom of the color pop-up there are a number of options/buttons (the first one is the square with the diagonal red line which is the option for no fill)
4 - selct the fourth option - pattern and select the pattern at the top of the color pop-up.
5 - if you want to use your own pattern or image, select the Other... option at the end of the list.
Hope that helps!