"iwlist scan" while hostapd running

[ramon at nanoair.com]

I am using hostapd to create an adhoc WPA secured wifi network,
everything is working fine. From another machine I can connect with no
issues.
However when hostapd is running, the command:

iwlist wlan0 scan

returns 

wlan0 Interface doesn't support scanning : Operation not supported

If I kill the hostapd process and bring up the wlan0 interface then
iwlist wlan0 scan works perfectly.
I want to be able to scan while hostapd is running. 
How to do this?