including child xsd into parent in external defination in PI 7.1

Hi team,

I got an error , when trying to include child xsd into parent .

My parent xsd contains two include commands pointing two child xsd file names.

I have imported all 3 xsd's in external defination.but when i import external defination (parent xsd) into message mapping ,the fields which are in child xsd's are not appearing.

Can anybody explain the procedure how to import child xsd's into parent xsd in PI 7.1.

Thanks

Drumi