How did Gandhi contribute to the Boer War?

Mahatma Gandhi founded an Ambulance Corps of around 1100 volunteers in support of the British in the Anglo-Boer War of 1899-1902. He thought that support for the British would translate into better conditions for Indians in Transvaal and South Africa in general. His hopes, however, were belied.
Since Gandhi participated in the South African wars albeit as a non-combatant he admits himself to have supported war. Even more directly by attempting to raise troops in 1918 to fight in the British army in the Great War he did help the war effort.