Flat file load

Hello

I am loading a cube through a flat file. For each field in the flat file, I have created a Z infoobject in BW. Eg - I have ZMATERIAL, ZPLANT and ZMARKET.

Now there are 2 navigational attributes of "0MATERIAL" that are also required in the cube. How can I get these nav attributes into the cube? Do I have to load 0MATERIAL into the cube from R/3 also? The values of these nav attributes cannot be directly provided to us from the flat file.

Thank you

Alex.