Official histories
Ministero della Difesa. Italian Official History: La Guerra in Africa Orientale, Giugno 1940 - Novembre 1941. Rome: Ufficio Storico, 1952
It has an english translation and if i have time ill look it over.
Hinsley, F. H. et al. History of the Second World War: British Intelligence in the Second World War: Its Influence on Strategy and Operations, volume one. London: HMSO, 1979
Italian East Africa- Somalia, Eritrea and Ethiopia, Sudan , Kenya 256,000 Italian nationals powed, total Native---182,000 powed, that does not take into acount any deaths, combat or otherwise.
The difference is probobly due to me citing what was taken at the conclusion of the campaigns, and your figures stating what was there initialy.
I will be near the PRO office in a couple of weeks time, if this topic is of some importance to you let me know and ill see if i can find the exact microflim archives for you.
Hanny