When handling an inbound SOAP message with a PartyInfo header with a non-default trading host, and the SOAP protocol disabled for the default trading host, BC fails to send a response,and throws the following error:

2014 Dec 22 11:33:48:556 GMT -8 BW.BusinessConnect-Interior_Server Debug [bw.logger] BW-EXT-LOG-300002 Job-29.29 Hibernation: Successful resurrection on key '9C36858D-A32D-49F1-AFD3-33B63985DD28'. 
2014 Dec 22 11:33:48:572 GMT -8 BW.BusinessConnect-Interior_Server Debug [bw.logger] BW-EXT-LOG-300002 Job-29.29 In com.tibco.plugin.gateway.InvokeOperationActivity.eval() : com.tibco.ax.soap.runtime.BCSoapOBBMHService.errorProcessor 
2014 Dec 22 11:33:48:572 GMT -8 BW.BusinessConnect-Interior_Server Error [bw.logger] BW-EXT-LOG-100000 Job-29.29 com.tibco.ax.fw.runtime.impl.ServiceException: Internal Server Error
at com.tibco.plugin.gateway.InvokeOperationActivity.sInvokeServiceOp(InvokeOperationActivity.java:258)
at com.tibco.plugin.gateway.InvokeOperationActivity.eval(InvokeOperationActivity.java:129)
at com.tibco.pe.plugin.Activity.eval(Unknown Source)
at com.tibco.pe.core.TaskImpl.eval(Unknown Source)
at com.tibco.pe.core.Job.a(Unknown Source)
at com.tibco.pe.core.Job.k(Unknown Source)
at com.tibco.pe.core.JobDispatcher$JobCourier.a(Unknown Source)
at com.tibco.pe.core.JobDispatcher$JobCourier.run(Unknown Source)
Caused by: java.lang.NullPointerException
at com.tibco.ax.fw.impl.db.DbConfigReader.getBindingAsInvoker(DbConfigReader.java:329)
at com.tibco.ax.soap.runtime.BCSoapOBBMHService.checkConfigForResponseAction(BCSoapOBBMHService.java:3178)

Activate the SOAP protocol in the trading host and create a BusinessAgreement between the default trading host and the trading partner and make it inactive.  This allows BC to work and process the transaction but will prevent the trading partner interacting with the trading host using the SOAP protocol.