Updating draft delivery isn't able to delete packages

Goodmorning,

Currently we face some issues while we are trying to update a draft delivery document inside sbo.

The method of the B1 object call is set to: Synchronous Insert with fallback to update.

For example when we have a draft delivery with the following amount of packages and we want to delete for example package 3 it doesn't work at all.

All relations from the items to the packages are also removed  before we send the xml towards B1if.

<DocumentPackages>
  <row>
  <Number>1</Number>
  <Type>Pallet 120x8</Type>
  <Units>3</Units>
  </row>
  <row>
  <Number>2</Number>
  <Type>Pallet 120x80</Type>
  <Units>3</Units>
  </row>
  <row>
  <Number>3</Number>
  <Type>Pallet 120x80</Type>
  <Units>3</Units>
  </row>
</DocumentPackages>

Once we send the update where only 2 packages exist, this will be the actual result:

<DocumentPackages>
  <row>
  <Number>1</Number>
  <Type>Pallet 120x80 UPDATED</Type>
  <Units>3</Units>
  </row>
  <row>
  <Number>2</Number>
  <Type>Pallet 120x80 UPDATED</Type>
  <Units>3</Units>
  </row>
  <row>
  <Number>3</Number>
  <Type>Pallet 120x80</Type>
  <Units>3</Units>
  </row>
</DocumentPackages>

So all changes are visible however not the actual removal of the third package.

Are we doing something wrong, or is this just not possible at all?

Kind regards,

Marcel Kieboom