QBO API V3 : Product Inventory is not getting updated - intuit-partner-platform

Question

We want to manually adjust/update the Inventory of an Item using QBO V3 API.
But, the QtyOnHand did not get updated on QBO properly. We re-checked using QBO browser app too.
First Request : Create a product of type "Inventory" on QBO with "QtyOnHand" set to 100.
a. The response appropriately mentioned that the product is created.
Second Request : Update the above product with "QtyOnHand" set to 200.
b. The response still contains the older QtyOnHand (100). It didn't reflect that new QtyOnHand.
How can we manually adjust / update QtyOnHand using QBO V3 API?
For reference, our update request is:
<IntuitBatchRequest xmlns="http://schema.intuit.com/finance/v3">
<BatchItemRequest operation="update" bId="0">
<Item>
<Id>2091</Id>
<SyncToken>0</SyncToken>
<Name>Product 26--var 2</Name>
<Description>false</Description>
<Taxable>true</Taxable>
<UnitPrice>1000.00</UnitPrice>
<Type>Inventory</Type>
<IncomeAccountRef>62</IncomeAccountRef>
<ExpenseAccountRef>111</ExpenseAccountRef>
<AssetAccountRef>112</AssetAccountRef>
<TrackQtyOnHand>true</TrackQtyOnHand>
<QtyOnHand>200</QtyOnHand>
<InvStartDate>2014-01-21</InvStartDate>
</Item>
</BatchItemRequest>
</IntuitBatchRequest>
Our response XML is:
<?xml version="1.0" encoding="UTF-8"?>
<IntuitResponse xmlns="http://schema.intuit.com/finance/v3" time="2014-01-20T23:21:44.559-08:00">
<BatchItemResponse bId="0">
<Item domain="QBO" sparse="false">
<Id>2091</Id>
<SyncToken>0</SyncToken>
<MetaData>
<CreateTime>2014-01-20T22:44:10-08:00</CreateTime>
<LastUpdatedTime>2014-01-20T22:44:10-08:00</LastUpdatedTime>
</MetaData>
<Name>Product 26--var 2</Name>
<Description>false</Description>
<Active>true</Active>
<FullyQualifiedName>Product 26--var 2</FullyQualifiedName>
<Taxable>true</Taxable>
<UnitPrice>1000</UnitPrice>
<Type>Inventory</Type>
<IncomeAccountRef name="Sales">62</IncomeAccountRef>
<PurchaseCost>0</PurchaseCost>
<ExpenseAccountRef name="Cost of Goods Sold">111</ExpenseAccountRef>
<AssetAccountRef name="Inventory Asset">112</AssetAccountRef>
<TrackQtyOnHand>true</TrackQtyOnHand>
<QtyOnHand>100</QtyOnHand>
<InvStartDate>2014-01-21</InvStartDate>
</Item>
</BatchItemResponse>
</IntuitResponse>

Answer 1

The QtyOnHand field is not an update-able field.
Inventory adjustments are made when:
You create a transaction that uses up inventory (Sales Receipts, Invoices, etc.)
You create a transaction that returns inventory (Credit Memos)
You issue an Inventory Adjustment (unfortunately, Intuit's API does not support this yet)
Given that the API does not support inventory adjustments yet, I don't think you'll be able to do what you're trying to do.