The CPayment.CreditCardNumber property throws an exception after upgrading to 15.1.2.x.  See two attached files for a console application and config file that test that everything is working correctly. 

... Yes, this is a working example once we got gor our upgrade issues resolved.  As stated in the comments below, you'll need to remove the BindingRedirect section in the config file to use the older imis 15 version of the payflowpro assembly. 

To create more than one instance of IMIS on a single server without using the multi-instance utility the following can be done.
1) Create the first instance and connect via the iMIS client and IMIS Public website to make sure that you can authenticate. The default installation location is the C:\Program Files\ASI directory.

2) Make a copy of the entire ASI directory and rename it to “ASI_SecondInstance” or another identifiable name. The path of the second instance is then C:\Program Files\ASI_SecondInstance. In this example ASI is the first instance and ASI_TAPA is the second instance. See the file system view in image one.