Employment Promotion

I am a Supervisory Special Agent with the Dept. of Justice, Immigration and Naturalization Service, (INS) GS-1811-13. I am highly qualified manager that is having difficulty being promoted within my own agency. I have been certified by other agencies for promotion to the next managerial level of Section Chief GS-1811-14/15. However, I am having difficulty being promoted within the INS since they have implemented a Promtional Assessment Test. In which, I scored poorly. The test has been widely scrutinized by Senior to Low Level Managers and Subordinates, because often the most qualified applicants are not getting on qualified applicant lists because of there low test scores. The test has little or nothing to do with my Job as a Supervisory Special Agent and there is little or know study material in order to prepare for the test. I am interested if I have any legal options? Please have someone contact me at (415) 844-5423. Thanks, Ray Greenlee