neither... nor/RelEx

Example : "I could use neither the lorry nor the van. " 
 		 	 _to-do(could, use) 
    			_quantity(lorry, neither) 
    			_det(lorry, neither) 
  		 	conj_nor(lorry, van) 
    			_obj(use, lorry) 
    			_obj(use, van) 
   			 _subj(use, I) 
I don't much like conj_either_or ... In English, people will say "Let's do A or B" in common speech, and they'll say "Lets do either A or B" to emphasize that there is a choice to be made, that it's important to choose.  Thus, "either" is acting as a modifier, its strengthening the "or", but not changing its meaning.  

That suggests that perhaps _advmod(or, either)  would be a way of indicating the "strengthening" of the choice.  

"neither" is mandatory: you cannot use "nor" in a sentence without using "neither", right?   But its mandatory only because of the strengthening function it has: it helps make clear that there's a negation, as otherwise one risks mis-hearing the "nor" as "or".