How to make attachments using class cl_gos_manager on key basis?

Dear Gurus,

I am using class cl_gos_manager to attach files in using generic object services of IFGOSXSERV sap.

But now I want to retrieve and save it on particular key basis.

i.e if I attach a document on particular capex number basis as supporting document, hence I could able to retrieve only those documents correspond to that capex number I saved..

thx in advance

Many Thanks / Himanshu Gupta