In Flash builder 4, Network Monitor feature supports monitoring network calls of secured HTTPService calls made out of Flex application.
There are two kinds of secured servers.
1. Secured servers with Self signed certificates
2. Secured servers with CA signed certificates (Eg. Verizon)
For the Flex application which connects to secured servers certified by CA, Network monitor bypasses the security checks and network calls will be recorded. But for secured servers which is having self signed certificate Network monitor will throw a SSL warning dialog alerting the user as "Network Monitor could not connect to the server due to self-signed certificate. Please select Ignore SSL security checks under Preferences to disallow certificate checks."
Note that all the HTTP Service calls which are made to secured server with self-signed certificate will fail.
To bypass the security checks and to monitor the network calls using Network Monitor feature in Flash builder, In Flash builder, goto Window->Preferences->Flash Builder -> Network Monitor. Select the check box 'Ignore SSL security checks'. This requires relaunching the application freshly. So, make sure that you close the application and relaunch the application.
Once you select the check box 'Ignore SSL security checks' you will be able to monitor network calls made out of Flex application to any secured servers using HTTPService.
Now, when the application is launched using Run/Debug mode, it will open up a warning dialog 'No SSL checks warning' as "Ignoring SSL security checks. If you want to allow certificate checks, then unselect "Ignore SSL security checks" under Preferences." This warning is just to notify the developer that he is bypassing the security checks. This warning will be thrown for both the network calls made to CA/Self signed secured servers. By closing the warning dialog developer can debug his application for network calls made to secured server using HTTPService.