The way I understand the {ja'chuqmeH rojHom neH jaghla'} is that it goes as:

(ja'chuqmeH) rojHom neH jaghla' = in order that some unstated parties
discuss with each other, the enemy commander wishes a truce. Perhaps,
this enemy commander is one of the parties involved, but what matters
is, that there could be an unstated subject of the {ja'chuqmeH}. So,
this sentence could actually be:

ja'chuqmeH (unstated parties), rojHom neH jaghla'.

The reason I understand this sentence this way, is that it sounds
weird to have {ja'chuqmeH rojHom} as in "confering truce". And even if
it doesn't, the problem still remains, that this Ca'Non example can be
interpreted either way.

Except TKD explicitly says this is a noun phrase, ja'chuqmeH rojHom:

The phrase ja’chuqmeH rojHom a truce (in order) to confer is the object of the verb neH he/she wants it

The object is a noun rojHom truce preceded by the purpose clause ja’chuqmeH for the purpose of conferring or in order to confer.

So the TKD example is exactly what you were asking about.

-- 
SuStel
http://trimboli.name