Wireless Issue

Hi... We have several new Latitude D630's and a wireless network with 5 access points (all the same SSID).  We are using the Dell Wireless WLAN Utility and as you move from area to area in our building the utility will not roam to the access point with the best signal.  It will always stay on the original signal it received.  Is there anyway to fix this?

 

Thanks in advance.