The following Automation types are supported by Microsoft Transaction Server.
| VT_BOOL | VT_LPSTR |
| VT_BSTR | VT_LPWSTR |
| VT_CARRAY | VT_NULL |
| VT_CLSID | VT_PTR |
| VT_CY | VT_R4 |
| VT_DATE | VT_R8 |
| VT_DECIMAL | VT_SAFEARRAY |
| VT_DISPATCH | VT_UINT |
| VT_EMPTY | VT_UI1 |
| VT_ERROR | VT_UI2 |
| VT_HRESULT | VT_UI4 |
| VT_INT | VT_UI8 |
| VT_I1 | VT_UNKNOWN |
| VT_I2 | VT_USERDEFINED |
| VT_I4 | VT_VARIANT |
| VT_I8 | VT_VOID |
The following types are not supported and will cause the server process to terminate with an error.
| VT_FILETIME | VT_BLOB |
| VT_STREAM | VT_STORAGE |
| VT_STREAMED_OBJECT | VT_STORED_OBJECT |
| VT_BLOB_OBJECT | VT_CF |