[TYPO3-mvc] adding n Objects from a single view

[Daniel Kürner]

Dear all, 

I have a class called "Dataset" and a class called "Tag". There is a 1:n
relationship betweeen both: One Dataset may 
have many Tags. The Dataset has a $tags attribute of type
objectstorage<Tag>. 

I am perfectly able to store one Tag within a newDataset. What I want to
achieve is, that the User may add multiple tags (for testing purposes 3) 
within one view. 
What I did is, I added 3 textboxes to my view: 
<f:form.textbox name="tag1"/> 
<f:form.textbox name="tag2"/> 
<f:form.textbox name="tag3"/> 

the submit leads to the createAction where I try the following: 

$tag1 = $this->request->getArgument('tag1'); 
$tagOne = t3lib_div::makeInstance('Tx_CrcData_Domain_Model_Tag'); 
$tagOne->setTag($tag1); 
$newDataset->addTag($tagOne); 

$tag2 = $this->request->getArgument('tag2'); 
$tagTwo = t3lib_div::makeInstance('Tx_CrcData_Domain_Model_Tag'); 
$tagTwo->setTag($tag1); 
$newDataset->addTag($tagTwo); 

and so fourth. 

But: Only one Tag Object is being persisted within the database. addTag()
should add all three instances to the Dataset Object ?! 

Any ideas on why it doesn´t? 

Big thanks 
Daniel