They invited them in and spoke to them about Islam. If these soldiers leave the masjid with an iota more respect for the Muslim traditions and Muslim beliefs, that can only be a good thing. The stories that we hear of British and American troops abusing Muslims are due to lack of respect, understanding and care for the Muslim way of life coupled with the animalistic and barbaric tendencies and hate that they conceal within their hearts. If there was one way to give dawah to them or to try and decrease that, isn't this the method?