You can configure the WAP to be a client of the LWAP. The WAP would act as a wireless bridge. It will not be a point-to-point link, but the WAP will bridge the devices connected to its ethernet interface to the LWAP.
Apparently, you can only configure this for one radio in the WAP. In the radio configuration, use the
station-role workgroup-bridge command. Cisco provides an example:
AP# configure terminal
AP(config)# interface dot11radio 0
AP(config-if)# station-role workgroup-bridge
AP(config-if)# ssid infra
AP(config-ssid)# authentication client username wgb1 password cisco123
AP(config)# workgroup-bridge client-vlan 22
One hitch is that the WAP as a bridge can time out the MAC addresses of the clients it is bridging, if they do not send very often, even if they are receiving. You can increase the timeout for this problem:
bridge <bridge-group-number> <aging-time seconds>
Cisco has the full set of instructions on configuring a workgroup bridge, e.g. Cisco IOS Configuration Guide for Autonomous Aironet Access Points Cisco IOS Release 15.3(3)JAB. In particular, there is a section on configuring a workgroup bridge, and a following section on how to work with a workgroup bridge as a client of an LWAP.
Understanding Workgroup Bridge Mode
You can configure access points as workgroup bridges. In workgroup
bridge mode, the unit associates to another access point as a client
and provides a network connection for the devices connected to its
Ethernet port. For example, if you need to provide wireless
connectivity for a group of network printers, you can connect the
printers to a hub or to a switch, connect the hub or switch to the
access point Ethernet port, and configure the access point as a
workgroup bridge. The workgroup bridge associates to an access point
on your network.
If your access point has two radios, either the 2.4-GHz radio or the
5-GHz radio can function in workgroup bridge mode. When you configure
one radio interface as a workgroup bridge, the other radio remains up.
However, both radios cannot be configured to operate simultaneously as
a workgroup bridge. The other radio can either be disabled (shutdown),
or be in root (access point or bridge), scanner, or spectrum mode.