[Typo3-shop] Individual/unique 'alttext' and 'tilteText'

[Jogvan Olsen]

Is it possibly to add individual/unique 'altText' and 'tilteText' to the 
products images?

I would like to have a 'altText' and 'titleText' like this:
[tt_products.subtitle], [tt_products.title] [this text is the same for all 
images]


I know I can add a standard alt/title text like this:

plugin.tt_products.listImage {
    altText = This is my alt text
    titleText = This is my title text
}

But how can I add subtitle and title to the alt/title text?

Thanks in advance
Jogvan Olsen