Past tense of the verb "FedEx"

Wiktionary suggests FedExed, which seems to be the most popular (see a google search), but Fedexed and fedexed are also common.

Also, Ngrams illustrates a definite preference for FedExed:

http://ngrams.googlelabs.com/chart?content=Fedexed%2Cfedexed%2CFedExed&year_start=1980&year_end=2008&corpus=0&smoothing=3

I would tend to go with FedExed because it is so popular, though I wouldn't disparage the natural Fedexed, or the inevitable fedexed (cf. googled, etc). In fact, I will probably change my mind in the near future and choose fedexed, since it's not at all ambiguous.

As an aside, it has become uncommon for 'd to be appended to form the past tense of a verb. It's most often used poetically, especially archaically, because it used to be necessary to specify when the -ed ending was pronounced as a separate syllable. (E.g. severed would have been pronounced 'se-ver-ed, whereas sever'd would have been 'se-verd.) Needless to say, this spelling contraction is no longer necessary.

Also, "-d" has never been common; in fact I've never seen it, so I would avoid it.

Lastly, a lone d is only used when the last letter of the verb to be past-tensed is an e, (e.g. file becomes filed - added d, but end becomes ended - added ed).

Addendum: appending ed is the best way to create the past tense of FedEx, rather than a single d, punctuated or not.