As one of the options, you can modify screen SIH field STOMVTFLG with default value Yes instead of empty one.

Thank you. How do i make it default to "YES"

As I replied before, modify according SIH screen, field STOMVTFLG with default value 2 if I recall correctly. If you do not know how to modify screens, then you need to ask this to programmers or more experienced collegue.

I have been trying to change the default from 'No' to 'Yes' without success in the screen. Is there a parameter or another setting that controls this default?

Actually with a some further research entering a Sales Order, creating a delivery and then an invoice, the invoice defaults to YES for a Stock Transaction.  Entering an invoice directly defaults to NO regardless of the default in the screen.

correct.  You can change it from No to Yes for a direct invoice entry but it has to be for a stock managed product.  and it has to be changed before you save the invoice - once saved it is disabled.

The Stock Transaction field appears above the detail line. You have to make the Stock Transaction determination choice before you enter detail lines. I am looking to have the Default to be YES.

We modified code to default to yes in SPESIH for custom counter invoices.

It is scattered throughout SPESIH with 9 mentions of STOMVTFLG 

Screen code with default to 2 but code is also needed. 

Steve 

In my case we need to import invoices, not key them in so I suspect that the IMPSIH script needs to be changed, agreed?

Hmmm....  I don't know.   On first glance i would say you need to add a specific script and not modify IMPSIH

Since it's an import can you add the field and import it or will the system override it?  sinvoicev_>STOMVTFLG is not in the import that i see.  I can't think of an instance where i passed a value in an import and the system changed it but I could be wrong and it's a special field. 

Yes. That is the solution.  Is this research for you billable.   From the online help.

Please accept as the answer.  

Import with stock movement

It is possible to import invoices with stock movement when this is a direct invoice provided that the imported invoice has the non-validated status. Otherwise, no stock movement will be carried out and the Stock movement flag will be set to No.
To import non-validated direct invoices with stock movement, it is necessary to add the field STOMVTFLG of the table SINVOICEV in the import template and to set correctly its value in the import file. The stock to be issued is determined by the allocation rules of the product category. Credit memos with stock movements cannot be imported in any way, the field STOMVTFLG is ignored in this context and set to No.

This led me to that.  

Import :
# - Utilisation de la transaction du paramètre TRSFAC
# ( pour utilisation eventuelle du Code mouvement stock )
# - Si import avec STOMVTFLG=2 ( m.a.j. stock = oui )

TRANSLATED 

# - If import with STOMVTFLG=2 ( m.a.j. stock = yes )

# Sortie de stock auto. : création des allocations détaillées
# ( Nota : les mvts de sortie sont créés à la validation facture )
# Pour les avoirs JAMAIS d'entrée en stock
# - Si import du calcul, le montant TTC doit être importé
# les tables SVCRVAT et SVCRFOOT doivent être importées
# les mnts des éléments de facturation saisis doivent être importées avec SVCRFOOT

Steve -

Thanks.  I did find a KB that claims that this behavior is 'by design'

https://support1.na.sage.com/selfservice/viewdocument.do?noCount=true&externalId=89114&sliceId=1&isLoadPublishedVer=&docType=kc&docTypeID=DT_Article&stateId=18980&cmd=displayKC&dialogID=864698&ViewedDocsListHelper=com.kanisa.apps.common.BaseViewedDocsListHelperImpl&openedFromSearchResults=true

I started going through the script to determine the criteria that would not allow the default to be 'Yes' but:

1. Am not totally familiar with the code.

2. Got tired or using Google translate.

And you can send me an invoice if you figure it out.