Before you can access the .tst files on this server from CTP, you need to add them to the TestAssets folder as follows (Test assets must be in this specific folder in order for CTP to access them)
1.Open API Testing
2.Select SOAtest server
3.Select action Create Folder
1.Create test scenario
Then TestAssets folder will be added automatically.
Thanks @Ireneusz Szmigiel for quick response.