Drilling into a tanked wall!

[susefox]

Hi there,

this question may have been put forward before, but here goes...

We are in a basement office and the back wall is completely below ground level. We have some bookcases that need fixing to stop them toppling over. The landlord says we need to get it done properly, I just can't find anyone with a definition of the word 'properly'! It is a tanked wall and I know if we breach any sort of damp proof course, we're in for it!!

Any help would be gratefully received!!!

Thank you.