We had a similar problem once, and we had no way we were allowed to install any external module at all.
What we did, is give the it-department of the company a list of prerestiqued modules, and let them do the installation of the server. Next, if the program failed due to the miss of one or more modules, they were responsible (and took that serious luckily)
I do think, if you explain and negotiate, a lot will be possible, and let your client participate. (and make him responsible)