First of all, we would like to stress that as a lawyer or a consultant, you should be committed to the principles and ethics of Islam. Your involvement in the system has nothing to do with labeling that system as being Islamic or non-Islamic.
However, for instance, if you were involved in a financial dispute, for example, then you are not allowed to help anybody for generating any interest because of that deal. You should always be in disagreement with interest, gambling or lottery. You cannot help a person who is a thief in order to make him innocent against your satisfaction. There is no evidence in the Shari’ah that generalize saying that your job is haram.