Need to suppress the authentication popup while consuming external web service in sap abap

Hi Experts,

While am trying to consume the external system web service,system always prompting the Authentication Pop up for User name and Password,

even am setting the password using the method authentication.

As the third party system instructions, user name and password should be encoded into base64(UTF8) format and need to set the value as header 'Authorization'.

The same is working,while using from c#,but in the sap abap even passing the converted user and password for the header 'Authorization'

still Authentication Pop up is raising at the time of calling receive method.

Please give me the suggestions to suppress the dialog popup.

Code Snippet used for authentication:

CALL METHOD cl_http_client=>create_by_url

EXPORTING

url = lv_url

ssl_id = 'ABCDE'

IMPORTING

client = lr_client

EXCEPTIONS

argument_not_found = 1

plugin_not_active = 2

internal_error = 3

OTHERS = 4.

CONCATENATE 'agc' ':' 'XXXXXXXXXXXX' INTO logon.

logon_b64 = l_utility->encode_base64( logon ).

CONCATENATE 'Basic' logon_b64 INTO logon_b64 "#EC NOTEXT

SEPARATED BY space.

CALL METHOD lr_client->request->set_header_field

EXPORTING

name = 'Authorization' "#EC NOTEXT

value = logon_b64.

CALL METHOD lr_client->request->set_method( 'GET' ).

"Calling the Webservice

CALL METHOD lr_client->send

EXPORTING

timeout = 200

EXCEPTIONS

http_communication_failure = 1

http_invalid_state = 2

http_processing_failed = 3

OTHERS = 4.

"Receive the Responce from the Web Service

CALL METHOD lr_client->receive

EXCEPTIONS

http_communication_failure = 1

http_invalid_state = 2

http_processing_failed = 3.

"Read HTTP RETURN CODE

CALL METHOD lr_client->response->get_status

IMPORTING

code = lv_http_status

reason = lv_status_text.

Thanks and Regards.

Y. Ravi Kumar.