[Avodah] Modim Modim

[Michael Kopinsky]

On 2/6/07, Micha Berger <micha at aishdas.org> wrote:
> (Granikim don't say it because the only "Hu" one can give a berakhah to is
> "Shemo". Once one distinguishes between the two, "Hu" refers to the Ein Sof,
> for Whom the concept of berakhah is meaningless.)

What is your mekor for this?  It fits with ideas expressed in Nefesh
Hachaim, but RCV does not say this mefurash.  Is it in Maaseh Rav
somewhere?