Mango contains plenty of vitamin A (http://www.thefruitpages.com/chartmango.shtml). I have some frozen mango which confirms this on the bag. However, a can of mango pulp says that it has 0% of the daily recommended amount. Why is that?
The vitamin loss is due primarily to the puree'ing. The viramin A in mangoes comes from beta-carotene, and beta-carotene breaks down easily due to oxidation. On a similar note, I've seen recommendations that carrots (another good source of beta-carotene) not be chopped into small pieces before canning to preserve their vitamin content.
Lots of vitamins are also destroyed by the heat of canning, but beta-carotene is not as susceptible to this problem because it is fat soluble.
On this website they say: "We take intensive care to retain the natural characteristics of taste, colour, nutritional value and flavour of the fruits."
So maybe it depends on the brand. Some brands use a more 'rougher' process than others, that could be the reason. I'm not sure though, but check out other brands, maybe some will have vitamin A in it.