This may be difficult.  We don't know of a way to keymove in advanced codes on a URC-8350. I'm reasonably sure that Tuner is EFC 00240, but that doesn't help us with the 8350.

Nor do we have a complete set of signals for the L40.  The NAD website does have IR codes for quite a few of their older equipment, but not for the L40.  It is possible to upgrade the 8350 by playing a WAV file while holding the remote next to a speaker, but it would be pretty laborious to try all the various possible  signals.

One obvious approach would be to use a Logitech Harmony remote.  They probably have the L40 in their database, and you can check that in advance of purchase.