I think there appears to be some difficulty amongst some posters from differentiating the general concept of belief as "propositions that we hold to be true" and the notion of conscious desire or decisions, and hence people seem to be equating the two.
I recently read an article on LessWrong.com that might help. The author provides two distinct terms in order to illustrate the difference between conscious decisions and subconscious truth values. He refers to them as Binary Beliefs and Bayesian Beliefs (they're big on Bayesian Probability theory on lesswrong.com). The article itself was about the notion of "belief in belief", the notion of claiming to accept something as true, or believing you accept something as true, without accepting it as necessarily true. Nevertheless, I still felt like its use of definitions to make the distinction is quite useful in this discussion.
In brief, the author defined Binary Beliefs along the lines of statements and actions. In other words, it is what we say we believe or what we may act as if it is true. We can choose our Binary Beliefs, because we can choose what we claim to believe, and we can still act as if something is true regardless of what we hold its true value to be. For example, we can say that we prefer to leave the house from our bedroom window, and may even decide to climb out of our bedroom window on occasion. So Binary Beliefs can be said to be chosen.
Bayesian Beliefs, on the other hand, are entirely involuntary. Bayesian Beliefs relate to the actual assessed probability we hold for given propositions in our minds, and this is not something that we can simply decide to change as a voluntary act of will. To use my previous metaphor, while you may choose to say your bedroom window is a good method to leave your house, and you may even choose to step out of your window if you really want to, no amount of will can alter the notion in your head that throwing yourself out of that window will not result in you falling several feet and likely hurting yourself. Without information altering your assessed probability, you cannot simply choose to believe that you are more likely to simply walk out of your bedroom window without falling than you are to walk out of your bedroom window and fall to the earth.
We can alter how we act to the world in accordance with personal desire, but we cannot voluntarily choose the propositions that we actually hold to be true as a matter of assessment, probability or personal acceptance. These beliefs are necessarily subconscious and involuntary, as we cannot simply choose to alter that which we feel we have already assessed, or the probability we hold for a given proposition. We may change how we assess or we may change the probabilities we assign to particular propositions, but the beliefs that result from these alterations are still a matter that decided subconsciously by the process utilised. Beliefs are the destination reached via given assessments of the information we have, and as such cannot be said to be beholden to our conscious will.