To emphasise what you've said, the root and brach reform that has happened in the RUC/policing in NI over the last decade (or more) can't be underestimated. Among the biggest factors, as I perceive them are both top down and bottom up:
* Engaging the civilian leadership of the effected Catholic/Republican communities in leadership and accountability positions (e.g. Sin Fein/Stormont)
* Making on the ground community relationships with the effected communities a huge priority, through: targeted engagement; community relations and frankly, demonstrating the RUC's value through active/effective community policing and crime reduction.
* The confrontation and acknowledgement of the previous injustices. Truth and reconciliation is key.
It's been a LONG and painful journey interlinked that isn't finished, but it really could serve as a great lesson to improving minority/police relationships in the US.