Replace tag in web sources framework

Is it possible to replace a tag if it's empty in a .src file?

For example, replace inside the loop:

Set "ITUNESACCOUNT" "me@email.com"
Say "|"

Set "ITUNESOWNER" "Name"
Say "|"

But I don't know how to do it only if the the tag is empty (doesn't exist).

No way to read tags currently with WSF. Write only. I'm pretty sure there's been a request for this already.