How to replace the spacebar rubber cap/nipple?

Macbook Pro 17", circa 2009. Spacebar was sticking. I tried cleaning. The white clips were fine. The rubber nipple in the center was cracked and in the process of replacing the white clips, the rubber nipple tore. I have replacement parts but I don't know how to remove the old nipple and install the new one. I do not live near any Apple stores or certified Mac repair people. The company where I bought the parts says to use super glue, but I have read that's not a good idea. In adddition, I can't see how to remove the old nipple. I'm using a bluetooth keyboard so that I can continue to work. This is my work unit and I cannot be without it for long. Any suggestions would be greatly appreciated. Thanks in advance.