SSO BW to EP

Is there a way that I can check that the SSO is working between BW and EP?

I can see that EP to BW is working, as I can login to EP, and see the list of queries (for example) under the metadata repository.

I am getting an error when I try to publish to EP from BW though, and need to know how I can test that SSO is working in that direction.

Thanks in advance for any help.

Regards

Richard