how to install CA certificate programmatically on Android without user interaction

I'm trying to install certificates without prompting the user. I know this is not good practice, but that's what PM wants.

Using KeyChain.createInstallIntent(), I can get Android to launch the certificate installation dialog by calling startActivity. However, when I pass the intent to sendBroadcast, nothing happens. Maybe the platform doesn't support this for security reasons?

String CERT_FILE = Environment.getExternalStorageDirectory() + "/test/IAT.crt";
Intent intent = KeyChain.createInstallIntent();
try {
    FileInputStream certIs = new FileInputStream(CERT_FILE);
    byte [] cert = new byte[(int)certFile.length()];
    certIs.read(cert);
    X509Certificate x509 = X509Certificate.getInstance(cert);
    intent.putExtra(KeyChain.EXTRA_CERTIFICATE, x509.getEncoded()); 
    intent.putExtra(KeyChain.EXTRA_NAME, "IAT Cert");
    EapActivity.this.startActivityForResult(intent, 0);  // this works but shows UI
    EapActivity.this.sendBroadcast(intent);  // this doesn't install cert
} catch (IOException e) {