Is this possible with a minor change somewhere, like changing a tiny if structure in the voting system? This request is not completly unreasonable and I would wish question2answer would provide a checkbox setting for "Allow user to vote on own posts".
If you wonder why we require this? We use question2answer as a FAQ, Q&A but also knowledge base because of its tagging, detection of duplication, detection of similar posts features. This means we have several questions answered by the same user. In a case where only one answer is possible and correct this is fine but for cases where there are multiple completly acceptable answers we wished that the voting system would give a feedback on the recieved quality of the different answers. Currently the creator of multiple answers can not show which one he favors more!