Gallagy's answer is right; it does mean allocate, but that word is too general: it is a specific kind of allocation. Mapping is when investors' money, allocated by a fiduciary to a given fund, is reallocated to another fund, in the absence of instructions to the contrary from the investor, when the fund in which it is currently invested is discontinued or becomes unavailable. So the idea is that the alternative to which the money is mapped is regarded by the fiduciary as an equivalent.

"Mapping is the default allocation that fiduciaries use when they eliminate a fund from their menu offerings. Participants who are invested in the eliminated fund are reinvested in the mapped fund if they do not affirmatively select an alternative menu fund that is still be offered. Many, many employees don’t pay attention to plan notices that a fund is being eliminated and are mapped to the default investment, so the mapping allocation often determines where the bulk of the eliminated fund investments will be reinvested."
http://www.forbes.com/sites/whynot/2014/03/29/the-problem-of...

SOP, for example, is Sal. Oppenheim jr. & Cie. S.C.A. They do Emerging Markets/High Yield Corporate Bonds - the sort of thing you can lose or make a fortune on very quickly. Mapping that, to UK Equities which are relatively safe, for the purpose of "Capital market assumptions – risk and returns", seems very dubious.

But that seems to be what your investment group is doing - they don't trade in SOP, they trade in UK Equities instead.

--------------------------------------------------
Note added at 12 hrs (2014-05-29 08:53:29 GMT)
--------------------------------------------------

Re Charles' answer - I imagine that's where they got the term from OK. But they are using it in a hypothetical situation where it doesn't really belong. I'm suggesting rewording to match what they mean.