Or if you prefer: "kindly add...", which is how it is done in the translations of Peruvian documents cited below. They use "Mr Notary", which is literally accurate and sounds OK in American English, though it doesn't seem so natural to me in British English. If the notary has already been addressed in the document, the words "señor notario" might actually be omitted, I think.

"Mr. Notary, kindly add the introduction and conclusion required by Law, insert the necessary documents and, once this has been done, convert this preliminary deed into a public deed. [...]

Kindly add, Mr. Notary, the introduction and conclusion required by law as well as any annexes and other inserts that may be necessary and forward notices thereof to the Public Register of Mines. [...]"
http://google.brand.edgar-online.com/EFX_dll/EDGARpro.dll?Fe...

There's another example of the same formula in here:

http://www.nasdaq.com/markets/ipos/filing.ashx?filingid=4894...

Note that "required by law" is used in other places in these documents too (and in many others). I think it's the way to do "de ley".


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Note added at 1 day8 hrs (2013-01-06 12:14:45 GMT)
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Thank you, Claudia, and the same to you!