It turns out it’s pretty straight forward but your phone must be rooted for this to work and you must have enabled usb debugging.

The process goes something like this…

First on your phone navigate to Settings -> Applications -> Manage Applications -> Handcent SMS and click the Force Stop button to close handcent sms.

Next we retrieve the preferences file where the password is stored:-

$ adb pull /data/data/com.handcent.nextsms/shared_prefs/
com.handcent.nextsms_preferences.xml

Then edit the file you just pulled, find and remove the line that looks something like:-

<string name="hc_password">0cc175b9c0f1b6a831c399e269772661</string>

Next we push that file back to the device as follows:-

$ adb push com.handcent.nextsms_preferences.xml /data/data/
com.handcent.nextsms/shared_prefs/com.handcent.nextsms_preferences.xml

Now open handcent sms and the password should be removed ready for you to set another!

Obviously the above commands should be entered on one line, line breaks have been added to wrap the content…