Importing test cases with Excel and XML

[Sreenivas]

I have imported testcases to Testsuite by using excel sheet(having 3
fields).Since i have

used 'Create a new version' dropdown option ,it created as many test
cases i have in excel

sheet.Later i updated the data in the excel sheet and i selected the
'Create a new version'

dropdown, then again new test cases ,as many i have in excel ,are
created.But where as in

case of XML import ,it is updating the old testcases with updated data
instead of creating

new ones , as it happened with Excel.

What i am expecting is it should update the old testcases with new
data , should show me

version data.(This is happening with XML import where as in excel
import this is not the

case.).

[Sreenivas]

And my question is Am i doing wrong?
or is it a bug?
Any help would be much appreciated!!
TIA,
Srinivas.