[tponzo]

Not to be picky (okay maybe a little picky) but will and shall are not interchangeable. Voice and level of emphasis are different.

WILL verb-transitive
To decide on; choose.
To yearn for; desire: "She makes you will your own destruction” ( George Bernard Shaw).
To decree, dictate, or order.
To resolve with a forceful will; determine.
To induce or try to induce by sheer force of will: We willed the sun to come out.

SHALL auxiliary-verb
Used before a verb in the infinitive to show:
Something that will take place or exist in the future: We shall arrive tomorrow.
Something, such as an order, promise, requirement, or obligation: You shall leave now. He shall answer for his misdeeds. The penalty shall not exceed two years in prison.
The will to do something or have something take place: I shall go out if I feel like it.
Something that is inevitable: That day shall come.