Over on the right there is a tab you can click for the Property Manager, below the tab you would click to access your Design Library.
I would show you a picture, but I do not have SW2009 loaded on my work computer.
Or am I misunderstaning your question? A screen shot of what you are seeing would be good.
Have you mapped the Custom Property File location (under Tools > Option > System Option > File location) to the folder where you have saved the tab of the property template.
And once you set the file location go to file > properties to see those properties you created using Custom Property Tab builder.
I was trying to use the Property Manager on the left side of the screen. The icons look almost the same and the word Property is in both names.