You can also try hosting your Flash application on SAP box. Following approaches can be used:
Method 1:
First, you need to create a BSP application -> Create -> MIME Object and import crossdomain.xml file and activate the application. Next is to execute transaction SIC with default settings -> Double click the default_host, go to the Default Service tab, and the select the newly created application from default_host/sap/bc/bsp/sap/. Save changes.
Then you have to navigate back and reactivate default_host.
Method 2:
Other option is by using ICMA for processing HTTP requests.
For more details, you can check this link:
https://www.asabau.com/2009/04/11/crossdomain-policy-file-in-sap-web-application-server/