@
beedaddy 
oops I forgot, I don't use Send To, Email and Save To - and this is one of the reasons why so.
Another way I can think of would be to create an empty library and use right click Copy to Library. You'll be prompted as to which custom columns should be replicated in the empty library, tick what you want then do Send To, Email and Save To from that library.
And lastly I think this may be what plugboards are for - I've never really understood them, I think its about metadata that's the proprietary readers know about - rather than what's embedded in the book - but I could be totally wrong on that.
BR