It will be difficult to help you without the full response content and the content of the request where it should be used. But what issue do you get exactly?
Do you have difficulties to extract the value or to reuse it?
The value in your response is HTML encoded so if you need to use it HTML decoded there's an option in the variable extractor panel to decode it.
Please provide more information so we can help you on this.
You already provided that response. I need to know what issue you have extracting that value?
If you have access to the Neotys Support the best would be to open a ticket and provide an export of your NeoLoad project.
As Nouredine suggests, a support ticket might be the best route as we can't test this to ensure it works. Assuming you know how to create a variable extractor, the left hand side would be...
<input type="hidden" name="SAMLResponse" value="
...and the right hand side would be...
" />
...meaning the resulting pattern would be...
<input type="hidden" name="SAMLResponse" value="(.*?)" />
