You can't, You can only reach HQ through, Your secret agent phone thing
Try using your spy phone or the map.
In the volcano. On the the map, click on the volcano and enter. you will be in the HQ.
You can't use your map to get to HQ but the easiest way is to go to the sports shop or the "Everyday Phone Facility" to get there. And you need to be an agent!!!
HQ pro is different to normal HQ from cod4 and 5. in 4 and 5 the points you had to gain to win was 250 points, and you could capture the HQ as soon as it was located on the map. on HQ pro the points needed to win has been reduced to 200 and when the HQ is located on the map there is a waiting period before you can start to capture it :)
use the map or spy phone.
In HQ, on the chest of drawers, under the map.
Click on your map of phone then chose a place to go if you don't have a phone then just use your map.
you click on the map and go where u want 2 go
It's on the green chest of drawers, below the map of the island.
Through chip and dales golf course in donalds dock(see map)
Today it on the monthly catalog on the page 11 Click on the bottom right window in the middle you will find it il GUARANTEE YOU WILL IND IT
Go to ski village on the map, enter the sports shop, go around to the changing rooms, click the 3rd one. That is a secret door to the HQ.