This sounds feasible.
From what I understand, genes could be selectively embedded (via an adenoviral vector, as discussed) to a region of the chromosome where transcription rates are moderate, so as not to overproduce various peptides.
I'm VERY skeptical of this process working on any compound other than polypeptides. However, this is completely feasible, and as some of the posts above mentioned, there are studies that have done just that; insert an adenoviral vector containing RNA/DNA coding for specific polypeptide sequences (the example given being prepro-orexin, apparently a precursor or transcript of orexin-a and orexin-b) into a host (mouse brain).
One thing that would concern me is that simple I.M injection of a large amount of this raaV could be non-selective. For example, if you weren't extremely careful with the vector, and where it would insert itself into DNA, it could inadvertently be overexpressed somewhere where it shouldn't. For example, if you overexpressed the prepro-orexin transgene in a large amount of tissue, rather than just the specific brain region where you'd like it to be, you could have all sorts of physiological side effects simply because your body is flooded with orexin. Obviously, with a little more time someone could tell you the exact dangers, especially if we knew the sequences where the raaV bound to to insert itself.
In summary, I believe this technology has some incredible potential and applications, and I'd love to know more about your experiences with it and details about the technology itself. However, there are a plethora of obvious risks to an operation like the one you've undertaken, and I would really hope you've gotten some concrete information from your supplier to ensure your safety.