Hello,
We can fetch data from BW and construct Cognos reports.
But I don't think so we can load data from Cognos/TM1 to BW.
The alternative way of doing so is we've to stage data from Cognos to any relational database table and then through ETL/DB connection, we can load data from the relational database table and store it in BW cubes/Dso's.
If your data is not too large, you can get it done through flat file upload as well.
Regards,
Antony Jerald.