Status of property in arbitration

A Partnership Deed with an Arbitration Clause is under arbitration.  The property of the firm has been mortaged by one of the partner "A " for his personal benefit,  without the knowledge of the other partner "B".  While proceeding now for Arbitration, should not the property be got into the case free of any liability by the partner 'A' before proceeding for valuation and networth of the firm for settlement by the arbitrator.  

Thanks for ur valued advice in advance.