Hello Stefan,
If you are using report manager, you can link epmdocument and wtderivedimage using "Derived From The Derived Image" link and reference epmdocument to epmdocument master to get the name and number.
If you are looking at SQLs you can use the below to get all representations.
SELECT edm.documentnumber, edm.name, edm.cadname, ed.versionida2versioninfo "Rev",
ed.iterationida2iterationinfo "Iteration", di.NAME
FROM epmdocument ed, epmdocumentmaster edm, derivedimage di
WHERE ed.ida3masterreference =edm.ida2a2
AND ed.ida2a2 IN di.ida3therepresentablereferenc;
Thank you,
Binesh Kumar
Barry Wehmiller