A virtual service for HTTP/S cannot URL decode the argument values which URL encoded for Shift-JIS character set when receiving requests. And the argument values become garbled Japanese characters.
It is impossible to determine the character set from the URL encoded argument values in the request at the server side, even if the request header includes the "Content-type" information, because the "Content-type" information is the definition for the body only. Then it is impossible to support the many character sets for URL encoded argument values at the server side. And CA uses only UTF-8 for the URL decode in virtual services.
The DevTest is worked as designed. There are not any solutions for this problem in the product's feature level.
However if the character set for URL encoded argument values can be detected from some kinds of rules(Example. from operational rules), then the character set for the argument values can be changed for URL decoding and get the suitable values by using the "Scriptable Data Protocol Filter" or the "Execute script(JSR-223) Step" after "Virtual HTTPS Listener Step". But this method is the customization.