I don't see this working either :( Have a look at this reference doc that asks/answers this question;
Q. Is the Cisco Aironet 1500 Series compatible with the Cisco Aironet 1400 Series and Cisco Aironet 1300 Series?
A. The Cisco Aironet 1500 Series is LWAPP-based and will not interoperate with autonomous Cisco Aironet wireless bridges or access points such as the Cisco Aironet 1400 Series and the Cisco Aironet 1300 Series in autonomous mode. In addition, it will not bridge to the Cisco Aironet 1300 Series in lightweight mode because in lightweight mode, the Cisco Aironet 1300 Series operates only as an access point (and not a bridge). The Cisco Aironet 1500 Series will, however, co-exist in the same WLAN as a Cisco Aironet 1300 Series in lightweight mode (for example, within the same wireless LAN controller or across multiple controllers within the same mobility group), allowing a wireless client to roam seamlessly between the Cisco Aironet 1500 Series on the outdoor network and 1300 Series Access Points on the indoor network.