I've been thinking about your question for a few minutes, and I am still not sure how to answer it. Partially, because "will" has been understood differently by different philosophers, and also because the concepts will and intentionality do seem to share some common features.

I think I'll approach it this way: Intentionality, in Husserl's phenomenological method, was a necessary element in all thought, in that all thought is directed towards an object. I'd say a sort of common sense concept of will would have it be a sort of internal motivation to action. Will may have an object as focus, but I do not think it necessarily must have one. We may feel compelled to do something without a clear idea as to its ultimate goal. Likewise, while one could will oneself to think about something, thoughts might also occur to a person without motivation. However, in so far as we are conscious of these unwilled notions our thoughts are "intentional".

I'll warn you though, these are kind of off the cuff remarks. Someone who has read Husserl more recently than I have might be better off making the technical distinction.