Thanks for your quick help.
I have tried using the information in tutorial without any success. I am not sure as how to proceed. It will really help if you can point to a documentation which is explaining the steps in using Native SQL in Teiid Designer or a sample VDB for reference purpose.
With the 7.7 runtime the only option you have is to use the native-query extension metadata property. On a source table/procedure you should be able to set the native-query extension property in the properties panel. If Designer does not show that as an option you may need something newer like 7.8.