Hi Naomi,
I did not understand your question completely, your source is InfoObject 0WBS_ELEMT. I tried it in my BW 7.30 sandbox and it works fine.
Prerequisite is that both source and target InfoObject are defined as InfoProviders to enable a 7.0 Transformation and DTP. You can do that - if necessary - by assigning the respective InfoObject to an InfoArea.
Firstly I created a new InfoObject ZWBSELEMT with template InfoObject 0WBS_ELEMT. Then I created a Transformation as shown in the screenshot.
In the next screen all transformation rules for every segment are automatically proposed correctly, except the one for InfoObject 0WBS_ELEMT to ZWBSELEMT. You have to connect them yourself as shown in the screenshot.
So yes, it's possible and probably fairly easy.
Best regards,
Sander