Alan, all those restrictions apparently did not always apply. This quote is from an article on black slave owners:
"The general practice of the period was that plantation owners would buy seed and equipment on credit and settle their outstanding accounts when the annual cotton crop was sold. Ellison, like all free Negroes, could resort to the courts for enforcement of the terms of contract agreements. Several times Ellison successfully sued white men for money owed him."

"On March 27, 1863 John Wilson Buckner, William Ellison's oldest grandson, enlisted in the 1st South Carolina Artillery. Buckner served in the company of Captains P.P. Galliard and A.H. Boykin, local white men who knew that Buckner was a Negro. Although it was illegal at the time for a Negro to formally join the Confederate forces, the Ellison family's prestige nullified the law in the minds of Buckner's comrades. Buckner was wounded in action on July 12, 1863. At his funeral in Stateburg in August, 1895 he was praised by his former Confederate officers as being a "faithful soldier."

Both quotes from: http://americancivilwar.com/authors/black_slaveowners.htm

Proportionally, free blacks in the South owned more slaves than Southern whites did. (ibid) Stan