Vested benefit account with investment

Hi , hoping someone could point me in right direction. I have Swiss nationality and also USA green card holder, came back to CH couple of years ago and now moving back to USA. I am considering to keep my pension in Switzerland ideally in the vested benefit accounts with investment option (looking at longer term perspective). Reading through the ubs, CS and other banks , seems that they do not provide this option to US persons . In worst case scenario probably would be to leave it in non investment account and pull out in couple of years (not an ideal scenario). I will be talking to few banks this week however wanted to ask whether USA persons could also park their CH pension in vested benefits accounts with investment option - thanks a lot