I mean, we're not far off in English using this term... because we just don't say things like job manager,

I think the "zakazka" could be considered a project, (haven't seen the particular contract), and in that sense, project manager would probably match the spirit of the term and sit just fine with your client.
Anyway the translation would go something like this:

If the employee is responsible for managing a job order (project), such employee is directly subordinate to the director of operations within the scope of the independent position of Project Manager.

I have no problem with putting "project" in parenthesis for clarification...I don't consider it embellishing.


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Note added at 32 mins (2011-01-10 17:34:54 GMT)
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http://en.wikipedia.org/wiki/Project_manager

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Note added at 1 hr (2011-01-10 18:30:21 GMT)
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Elizabeth raised a good point, but I'd never turn this in as the 100% right term without having consulted with customer as to what the SCOPE is, and after a good kudoz exploration amongst the "proz"...