Many people visit that forum that have made such models.
See if you can contact Hydrocarbon Processing Magazine (Gulf Publishing) and get a reprint of an article that is titled "How to stress analyze jacketed piping" that they ran in the February 1978 issue of their magazine (subscribe while you are there). Be aware that C2 is a beam theory program and it will not address the critical buckling loads that typically occur in theses systems. Ben Nottingham (bnottingham@chartertn.net) has developed an MS ExCel spreadsheet that will address these loadings.