As far as i aware,You may try,IAP VPN Controller
http://community.arubanetworks.com/t5/Controller-less-WLANs/How-to-configure-basic-IAP-VPN-Controller-Configuration/ta-p/175014
http://community.arubanetworks.com/t5/Aruba-Solution-Exchange/Create-VPN-Tunnel-from-IAP-to-Mobility-Controller/ta-p/202669
Summary
Aruba Instant support building secure VPN connections to the head end Mobility Controller (MC). This allows wireless and wired users to access the corporate network's resources seamlessly. The traffic forwarding mode is determined by the selection of the station IP address assignment (VPN Mode).
IP allocation by the DHCP daemon in IAP is unique. User specified, the start and end IP address which could be a relatively large subnet, example 172.16.0.0/16. This large subnet will be further subnet by the controller based on the client count specified by users in the IAP. This process is automatic and no configuration is required. The calculated networks range will then be sent back to the IAP once the VPN is established. The following VPN modes are supported:
- Distributed L3
- Distributed L2
- Local *
- Centralized L2 *