Many different readings by WCW are set out here:
http://writing.upenn.edu/pennsound/x/Williams-WC.html
This includes many readings of "This is just to say," though I haven't found the language you are looking for. This one comes closest, though it's cut off just before WCW might have said what you report he said:
http://media.sas.upenn.edu/pennsound/authors/Wi lliams-WC/07_Van-Nuys_11-16-50/Williams-WC_07_This-is-Just_Van-Nuys_11-16-50.mp3
[This message has been edited by Roger Slater (edited February 16, 2008).]