Basicly, it might take pretty long time if you haven't yet worked with any kind of IBM WebSphere products.
I found most IBM Websphere exams related to WSAD very specific - a lot of questions actually assume that you had worked with certain
IDE wizards to create classes, entities, objects, etc.
IBM also provide its own view on j2ee
patterns, and sometimes it really confuse about IBM own patterns used to create for example web projects.
You can read the books quickly, but w/o actual hands-on experience it will be very hard to get high score.