The point of departure is that a person who physically exclusively performs his/her job functions in Denmark is comprised by Danish social security rules.
You could be member of a A-kasse in Denmark, BUT you would not be eligible to get benefits, beacuse you are not comprised by the danish security rules, as long as
you work in Uganda.
If you have been living in Denmark and is now posted by the danish company to work for some time (up to 3 years) in Uganda, you are comprised by danish rules.
If thats the case please contact an a-kasse for further advise about your rights to be member/get unemployment benefits.