On a very simplistic level - the main benefit of setting up a pension fund or PRSA is the tax relief you can reclaim from income tax paid.
The 'cost' of this tax relief are the restrictions placed on what you can do with a pension fund i.e. mainly you can't get at it for years and years but also you must buy an annuity etc
If you cannot get the benefits such as the tax relief or the employer's contributions , then you would be better off not tying your money into the restrictions.
Set up an ordinary equity fund (e.g. Quinn-life Freeway) and when you return you can then do what you want with this money, including using it to set up a pension or as AVCs.