not sure either what is the problem you having but
1-You need to open port 4500 udp and 69udp(if you upgrading firmware) on firewall
2-You need to add that AP to the rap whitelist
3-you need to add a pool of address on the vpn services
Here is a document in which it will tell you how to set it up...
You ignore on configuring the rap as you just need to convert it from instant to rap in that case, or you can do it automatically with aruba activate
If this is not what you are asking for please explain what part doesnt work or where you are confused.