I am not sure if you are a trial user or if you have already purchased StrataFrame. However, if you have purchased StrataFrame you also get the source code so you can see what is going on under the hood.StrataFrame is very extensible, so yes, you can overwrite the Save methods of the BO (which is all the form and maintenance form toolstrip calls) and implement whatever type of functionality that you would like. The BOs already have built in methods for serialization and deserialization as well which is something that you will need in order to physically separate the tiers. You can serialize to a byte array or a stream (including a network stream) and pass it between tiers.
In fact, there is a simple sample that shows how to overwrite the Save method of a BO in order to implement XML as a data source. You can see this within the Sample Console or open the C# or VB.NET sample of the XML data source and see how it works. Keep in mind that this is not an "apple to apple" sample, it just shows that the Save can be overwritten...and in your case you may want to serialize a BO.
But in short, yes, the framework is very extensible and you can inherit our business layer and add your changes so that you do not have to make these same changes for each BO you wish to pass back and forth.