Dunno how well this works in Blogger's tool. The IME doesn't seem to work inside this.

??????(konban wa)
??????? (oyasumi nasai)

I actually had to compose those in another application, then past them in.

And... they display as all ?????s. Probably because I don't have the proper language setting in the <HEAD> element. Mmm, nope, Blogger chokse on them entirely. Looking at the HTML source generated, it converted them to ?????s.

Oddly enough, they show up properly inside of the Blogger edit window.