La grilla tiene que tener las columnas que estamos enviando a insertar:

const tabla = BizuitForm.controls['grdTable_01'];
const rows = await tabla.value;

rows.push({
    CompanyName: 'TEST',
    ContactTitle: 'TEST',
    CustomerId: 'TEST',
});
tabla.value = {
    pages: {},
    rows: rows
};

Para editar un registro seleccionado:

var selectedRows = await BizuitForm.controls['grdTable_01'].selected;
if (selectedRows && selectedRows.length) {
    const selectedRow = selectedRows[0];
    var allRows = await BizuitForm.controls['grdTable_01'].allRows;
    const index = allRows.findIndex(x => x.CustomerId === selectedRow.CustomerId);
    if (index > -1) {
        allRows[index]['CompanyName'] = 'NUEVO NOMBRE';
        BizuitForm.controls['grdTable_01'].value = {
            pages: {},
            rows: allRows
        };
    }
}

Para eliminar un registro seleccionado:

var selectedRows = await BizuitForm.controls['grdTable_01'].selected;
if (selectedRows && selectedRows.length) {
    const selectedRow = selectedRows[0];
    var allRows = await BizuitForm.controls['grdTable_01'].allRows;
    const index = allRows.findIndex(x => x.CustomerId === selectedRow.CustomerId);
    if (index > -1) {
        allRows.splice(index, 1);
        BizuitForm.controls['grdTable_01'].value = {
            pages: {},
            rows: allRows
        };
    }
}