What he means by the veil of ignorance is that, for the purpose of his thought experiment, the hypothetical person wouldn't know what class they would belong to or what their economic situation would be. If they were placed in that situation, and asked to design the ideal society that would be suited to their needs, Rawls argues that they would always choose to create a society that looked after the least fortunate, because they were as likely to wind up in that group as in any other. Rawls's point was to provide a rational, social contractarian basis for a just and equitable society. So the idea of a veil of ignorance was essential to his argument. It seems that what you are saying is that self-interest, which is based on class and economic situation, is inseparable from one's view of the best possible society, and that is a fairly common critique of Rawls's theory.

I'm not sure I understand your question.  Are you saying you think that being in the veil of ignorance is unjust?  If so, I think you are wrong.  Different castes, etc. do have different needs.  But that is precisely why you must be in the veil of ignorance.  You have to be in the veil so you do not favor one group (presumably your own) over the other.  You have to do what is best and most just for all groups, regardless of what any particular group would prefer.