It worked now and answer is not doing a regular dll register with regsvr32 but using batch file. Take old Sonar MIDI plugin dll and put in the shared midi folder then follow batch file dll registration as administrator instruction of at the other forum and then rescan. Thank you many times to colinjamieson and markleford for sharing the investigation.
Forum does not allow me to make links. For other forum search cakewalk forums for '64 bit MFX and DXi development: Where do I start?' scroll down to colinjamieson first answer on August 25, 13. Read his post to get details but key part is in his words
9 -copy the .dll from the debug or release folder (as the case may be) and stick it in C:\Program Files\Cakewalk\Shared MIDI Plugins\
10 -Create a .bat file in the same directory, and put the following line inside of it (replacing MyPlugin.dll with the actual name of your own plugin):
11 -regsvr32.exe "C:\Program Files\Cakewalk\Shared MIDI Plugins\MyPlugin.dll"
12 -Right-click on the .bat file and select "Run as administrator"
13 -Rock and Roll