Reason for the error occurrence - "Element Not Found"

Hi,

I am developing smartGWT application and using selenium junit testing.
While testing the smartGWT application, i got the following error.

com.thoughtworks.selenium.SeleniumException: ERROR: Element
scLocator=//IButton[ID="isc_IButton_0"]/ not found

Actually, To run a smartgwt program in a mozilla browser, we need to
install gwt developer plugin for the appropriate browser. Only then the
smartgwt program will run. I have installed the gwt developer plugin to
the firefox successfully.

But when i run the selenium test case through junit, The program lauches
a firefox browser. But that is a plain firefox browser. i mean, it does
not have gwt developer plugin. So that, The above error occurs.

Can anybody tell me how to avoid this plain browser. Instead the program
has to launch default firefox browser(parent browser) which only
contains gwt developer plugin installed.

Please help me to solve this issue.

Regards,
Nobel.