we *have tested the steps that are outlined in the pdf document and been able to successfully create a checkout process using sage pay.
to trouble shoot the problem, see the "Debugging eCart Transaction Failed issues" tutorial on the eCart support page in the how to section for details on how to get the response back from sage pay in order to trouble shoot what the cause of the problem is:
ecart/
I'm not sure how you can say we do not support sage pay, we have done a lot of updates recently to accommodate changes that have been made in the transformation from Protx to Sage Pay.
