Syntactical ambiguity in introductory phrase reference: reference to main verb vs. object

Motivated by A, we outline our proposal for B.

Does “Motivated” refer to outline or proposal? It seems to me that a reader could infer one of two statements:

1. A motivated us to create this outline, or
2. A motivated us to create this proposal

As the author of this sentence, I am struggling a bit in how to fix the ambiguity, especially if (for other reasons) I would like to keep A in an introductory phrase.

From common sense, I suspect most readers would infer meaning #2 — the intended one by the author. But, from a grammar point of view, I am not sure if the introductory phrase has to refer to the verb (outline) or it could just as well refer to the object (proposal)? So does such a construction always modify the verb? Or how could we specify if we wanted to modify the object only?

I.e., how could we cleanly manage the ambiguity in favor of meaning #2?