try 
    {
        var Enroll = cadesplugin.CreateObject("X509Enrollment.CX509Enrollment");
    }
    catch (e) {
        alert('Failed to create X509Enrollment.CX509Enrollment: ' + cadesplugin.getLastError(e));
        return;
    }

    var AllowNone                  = 0x00000000;
    var AllowNoOutstandingRequest  = 0x00000001;
    var AllowUntrustedCertificate  = 0x00000002;
    var AllowUntrustedRoot         = 0x00000004;
    Enroll.Initialize(0x1);
var sPKCS7 = "-----BEGIN CERTIFICATE----- твой сертификат -----END CERTIFICATE-----";    
        try 
    {
    Enroll.InstallResponse(AllowNone, sPKCS7, 0x7, "");
   }
    catch (e) {
        alert('InstallResponse ERROR: ' + cadesplugin.getLastError(e));
        return;
    }