Long running workflow versioning: where and how to use OnActivityExecutionContextLoad?

We have a long running workflow which uses SQL tracking service (.Net WF 4.0). In the next update, we would like to introuduce a public property in one of the arguments of the workflow. Since this is breaking change, the persisted workflow inatances throw the following error on re-loading:

System.Runtime.DurableInstancing.InstancePersistenceCommandException: The execution of the InstancePersistenceCommand named .. LoadWorkflow was interrupted by an erro开发者_JAVA百科r.

InnerException: System.Runtime.Serialization.SerializationException: 'Element' '_x003C_BookmarkName_x003E_k__BackingField' from namespace '...' is not expected. Expecting element '....'

I understand this is a typical versioning issue and one of the recommendations I noticed on some of the sites is to override OnActivityExecutionContextLoad method and fill in the missing values. But I am not sure where and how to do this! OnActivityExecutionContextLoad is declared in System.Workflow.ComponentModel.Activity (.Net 3.5?) whereas what we have is a code-based top-level custom activity derived from System.Activities.NativeActivity (which receives the argument in question). Can something be done in this class to initialize the missing property of the argument?

All suggestions are welcome :)