Ann: FY14 Results Investor Presentation, page-52

To attempt to answer your question:
We are not valuing one contract (or more relevantly all existing contracts). We are valuing the entire cash flow streams of the business (both present and prospective). The recurring revenue streams that you refer to will correctly be included in the EBIT line which flows through to FCF. However, the growth capex which is being done to ensure that further future recurring revenue is accrued must still be accounted for. Ignoring it would mean that any growth in future cash flows embedded in your valuation would not be fair.

If I follow what your saying and if that is that you are trying to say that you are not including any growth in your valuation, then yes you can ignore the growth capex and only subtract maintennence capex to arrive at a DCF val for Vocus. But that valuation will not truly reflect the company that you are analysing. It would reflect a "what-if" scenario. Whether you want them to or not, they are continuing to make growth investments and so you must account for that.
As Ves states, growth is not free, and can sometimes be value destructive - so to ignore growth is not always conservative (as many may think).