I think a year of voluntary service with an organization, governmental or not, Canadian or not, of your choice, could be a way of overcoming this hurdle. Another advantage of it is its flexibility and compatibility with other governments. For example, if a person wants to immigrate to Canada, he'd be required to fulfil this obligation too. But if he'd done it already in his own country, and he has proof of it, then we could count that as fulfiling the requirement. If not, then he can go do taht and come back in a year, or volunteer in Canada for a year, as he wishes. But regardless, the requirement would have to be fulfilled. Even if he can't walk, there are secretarial and other polisitions too.