HTTP Internet Exception during 'Data Send': 'An error occurred in the secure channel support', code:

Hello ,

we have one requirement where we are calling outbound webservice and getting and error 

below is the setup 

outbound weservice is called from a Workflow which wal called from write record of script in Direct DB mode .

Webservice configuration :

its a HTTPS webservice ie URL is HTTPS 

Transport : HTTP 

Address : https://XXXXXX.com

Binding : SOAP_RPC_ENCODED

while calling the webservice we are giving one extra parameter --> siebel_transport_header:Authorization="Basic XXXXXXXXXX="

this webservice call is failed with the below error when it called from direct DB mode

"Error invoking service 'SiebelServiceSoap', method 'UtilizationDetails' at step 'Call Webservice'.(SBL-BPR-00162)