RQM : updating TestSuite custom Attributes using excel export?

RQMAPI document mentions that "customAttributes" is a supported resource for "TestSuite".

However config entries below do not produce desired result in excel export although the customAttribute is created in "Test Suite" custom attributes section.

testsuite.customAttributes.name="TestSuiteField"
testsuite.customAttributes.identified=M
testsuite.customAttributes.name=O
testsuite.customAttributes.value=P

Or other form as well (and combinations of if as well)

testsuite.customAttributes identifier="Custom_attribute_0_".name="testsuiteCustomAttribute1".type="SMALL_STRING".value=O

The data is not populated onto the custom Attribute fields!

Thanks in advance for your inputs.
Best Regards, Sunil