Ink Fill with Semigloss Enamel??

Hello All,

Does anyone have experience filling engraving with semi-gloss enamel paint?  One of our customers specifies this kind of marking as opposed to a lacquer ink stick.  We are finding that this process is very laborious and not cost effective for our customer.  We would be forced to inject the paint manually using a syringe. 

Does anyone have experience using another method??

Any help is greatly appreciated!

-Kiel