Editing transfer entries and -ve inventory

Could you please help me in my query as mentioned below?

We have started using navision from last few months. Being not so familiar with Navision, our team entered inventory entries in Navision in wrong sequence from old System (tally). These entries included transfer from one location to other as well.

Now problem we are facing is e.g. we have missed a entry before the transfer entry. Before reliazing about this error or before understanding this error we had already posted entry for transfer and navision had correctly done valaution for transfer based on FIFO. Now due to insertion of additional entry before transfer entry we need to revalue this transfer entry as well, but problem we are facing is we can revalue the entry in receiving location as its being positive entry but we cannot do that in sender location as it says outbound entries cannot be revalued.

Further my question is my Navision is allowing me to book sales / transfer of a item even though i donot have enough quantity in stock. This is giving me threat of -ve inventory.

Thanks in advance for your valuable time in looking at this query.

Navision shows stockout warning if stock goes out of inventory and never stopes you booking the invoice.

Best is that we can out a validation for restrict user not to book the invoice /order when inventory is out of stock.