So, I'm not really sure if the below is the "correct" thing - I just managed to patch it together by reading from the PD source.

You can find the code in:

• https://sourceforge.net/p/sdaaubckp/code/HEAD/tree/xtra/puredata/external-sendtest/

The help patch looks like this:

Basically, this is a copy of [send], which when banged, triggers r AHA and r EHE - even if there aren't corresponding send objects. It turns out, there must be a pd_bind in order for this to work, and for a long time I thought the object argument there is the sender object - but actually it seems to be the receiving object reference. So this objects includes an additional "dummy" receiver class, a copy of [receive], which is there simply to initialize this binding, once this is done, other normal [receive] objects begin reacting on messages too.

Now I noticed I don't actually have the code for setting [value] variables there, but it is easier - you simply declare a symbol, and then you call PD functions on it:

  t_symbol* s_mysimbol;
  ...
  x->s_mysimbol    = gensym("myvar");
  ...
  // initialize/instantiate the [value] variables (reading is with value_getfloat)
  // note - via value_get, these will also gain non-null ->s_thing property
  value_get(x->s_mysimbol);
  ...
  value_setfloat(x->s_mysimbol, 42);
  ...
  value_release(x->s_mysimbol);