Go to a better shop, or find a competent wheel builder to mate the new hub with the old rim.
If you have $ to burn, then get a new hub and rim. Use the OEM wheel for backup. I prefer the Mavic A319 over the stock Alex...more durable rim. Be sure to pick a SON 28 with at least 32 hole. 36 hole is best for touring.
There is no way you can build a high quality rim on the 1st try. Too many tricks of the trade to learn.