Run Powershell script with parameters containing special chars

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Hi
I have a Powershell step launching Test.ps1 ,in Input section I have 2 params which are 2 macros %MyParam1% and %MyParam2% (see the attach).
The problem is MyParam2 contains special chars [% so the step fails:
Error expanding macros or script in property Parameters: Test2]<Error parsing macros at position 8>
I tried as well with a batch step and it fails also:
Error expanding macros or script in property command: C:\Windows\System32\WindowsPowerShell\v1.0\powersh ell.exe -nologo -noninteractive -executionpolicy Unrestricted "& 'C:\Program Files\VisBuildPro9\Test.ps1' -Param1 'Test1' -Param2 'Test2]<Error parsing macros at position 8>'

Is there any way to launch the script Test.ps1 with second param containing special chars?