1. Mix all marinade ingredients; set aside.
2. Core, rinse, and thoroughly drain lettuce.
3. Chill.
4. Place cauliflower and green beans in saucepan.
5. Cover with boiling water and let stand 5 minutes.
6. Drain well.
7. Hold under cold water until cool, then soad in cold water 5 minutes.
8. Drain thoroughly.
9. Place potatoes and carrots in 2 quart saucepan.
10. Add water and boil until tender-crisp, about 5 minutes.
11. Drain; rinse with cold water.
12. Drain thoroughly.
13. In large bowl, toss cauliflower, beans, potatoes, carrots, mushrooms and olives.
14. Pour marinade over vegetables; toss again.
15. Cover and refrigerate 24 hours.
16. At serving time, slice lettuce crosswise into 1 inch thick slices, then cut lengthwise into chunks.
17. Toss vegetables with lettuce chunks.