OpenWrt with multiple radios

Question

I have three Compex boards running OpenWrt. I have connected two Qualcomm radios to each of the boards. I am trying to configure one of these boards as an access point (AP mode), and other two in station mode (STA mode). I bring up two Wi-Fi interfaces — wlan0 and wlan1 — on the AP (configured to use two different SSID's) as:

config wifi-device 'radio0'
        option type 'mac80211'
        option channel '165'
        option hwmode '11n'
        option path 'soc/1b500000.pci/pci0000:00/0000:00:00.0/0000:01:00.0'
        option htmode 'HT20'
        option disabled '0'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'W0'
        option encryption 'none'

config wifi-device 'radio1'
        option type 'mac80211'
        option channel '153'
        option hwmode '11n'
        option path 'soc/1b700000.pci/pci0001:00/0001:00:00.0/0001:01:00.0'
        option htmode 'HT20'
        option disabled '0'

config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'ap'
        option ssid 'W1'
        option encryption 'none'

In one of my stations, I enable radio0 and in the other one I enable radio1.

config wifi-device 'radio0'
        option type 'mac80211'
        option channel '11'
        option hwmode '11g'
        option path 'soc/1b500000.pci/pci0000:00/0000:00:00.0/0000:01:00.0'
        option htmode 'HT20'
        option disabled '1'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'none'

config wifi-device 'radio1'
        option type 'mac80211'
        option channel '11'
        option hwmode '11n'
        option path 'soc/1b700000.pci/pci0001:00/0001:00:00.0/0001:01:00.0'
        option htmode 'HT20'
        option disabled '0'

config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'sta'
        option ssid 'OpenWrt'
        option encryption 'none'

AND

config wifi-device 'radio0'
        option type 'mac80211'
        option channel '11'
        option hwmode '11n'
        option path 'soc/1b500000.pci/pci0000:00/0000:00:00.0/0000:01:00.0'
        option htmode 'HT20'
        option disabled '0'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'none'

config wifi-device 'radio1'
        option type 'mac80211'
        option channel '11'
        option hwmode '11g'
        option path 'soc/1b700000.pci/pci0001:00/0001:00:00.0/0001:01:00.0'
        option htmode 'HT20'
        option disabled '1'

config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'sta'
        option ssid 'OpenWrt'
        option encryption 'none'

Then I assign ip addresses:
On the AP:

ifconfig wlan0 1.1.2.52
ifconfig wlan1 1.1.3.52

On one station:

ifconfig wlan0 1.1.2.61

On the other station:

ifconfig wlan1 1.1.3.61

Then I add all the required ARP entries of the AP to the stations and the stations to the AP using commands similar to:

arp -i wlan0 -s 1.1.2.61 hw_address_of_wlan0

But I am only able to get one of them to send ping messages at one time (either I am able to send traffic over wlan0 or wlan1). Can someone tell me how can I get both wlan0 and wlan1 to send traffic simultaneously?