I refer to the 2 Divisions of the Waffen SS raised in occupied Belgium during the Second World War and see the ideological position of Irishmen joining the British Military, from occupied. Ireland, during the First World War as no different. Both were supporting what they considered to be the legitimate governments of their respective countries, full independence having become history.
Deschelles, the supremo of the Belgian SS got away to Franco's Spain, but most of his men were rewarded for their heroic and effective fighting on the Eastern Front by being shot dead by public firing squads under the orders of the Belgian terrorists after the War (they're not referred to as "terrorists," of course, because they won!) Franco's Spain, meanwhile, held a public Catholic Mass, every year, in memory of Hitler.
There's a point at which public religious commemorations become a political statement. Is a gung-ho British poppy jamboree appropriate to an Irish church such as ours? The Paddy-bashers of Belfast wear them with disdainful conquistadorial pride, while, during the Second World War the British Legion, who issue the poppies, helped Irish soldiers desert and go to Belfast to join the British forces. The Paddy-bashers were remarkably slow to join, incidentally, to the consternation of Northern Ireland Prime Minister Anderson.
On Good Friday, we have a commemoration of all the fallen, named without ranks or the outfits in which they fought during the recent fighting in this country: we don't have an Easter Commemoration of I. R. A. operatives with Easter Lilies etc, which would be equivalent to the British Remembrance Day commemoration.
Perhaps the latter should be modelled, in it's neutrality, on the Good Friday service in the Dublin Unitarian Church (for instance: remembering all who died in all wars) and held at a totally different time of year so as not to be seen as a British commemoration by stealth (despite the coincidence of November being the appropriate month during which to remember the dead).

Aindrias Baoighiil.