Thanks Alexandre!
It didn't work before because I used [sprintf %s%s]
If you're using cyclone's [sprintf], it can generate symbols with the "symout" argument. This joins several items separated by spaces into a single symbol. But, as I explain in its help file, this is basically useless now as you can just escape spaces with backslashes...
I also updated the help file of [makefilename] to show how to use backslashes in that object, as well as the iemguis' help file to show how you can set labels with spaces too.
cheers