Advice - Working remotely for Belgian company (Brussels)

Hello,

Hope this is in the right tab, it isn't specifically looking for a job, but is for advice on employment. I am looking for advice on working for a Belgian company in future. I am currently in China, and this company is a 'subsidiary' (though independently registered in Belgium), I will be moving back to Europe to look after this business.

However I have a choice. Being originally from Ireland I will live most likely in Northern Ireland, though could also be the south closer to Dublin should my wife find a job there. I can therefore either

1. Be employed under a Belgian contract for this company working remotely or
2. Have my own registered company in the UK or Ireland and invoice my time to the Belgian company for services etc. (to the agreed salary and so on)

I have many questions, particularly if there are any others with similar experience before? For example, income tax in the UK is residence based so I will be paying that on UK rates, however I am unsure how social security, National Insurance and pensions (and many other things) will work from another EU country. In Belgium is it normal for pension contributions to come out before tax, and do Belgian companies match contributions of employees?

Any advice or links pointing to further information is most welcome, it is a big decision to make. I think the protection offered by a contract from the Belgian company would be better than having my own, especially as I will be dealing with a Chinese company and all that entails, though possibly other restrictions may prove more difficult.

Thanks for all your help,
Kind regards,
Eugene