Transfer Value From Combox To Textbox

hi, umm im tring to copy values from a combobox into a textbox so that multilpe values can be saved on the databse.

the textbox it linked to a table, and the combobox uses sql quries 2 get data from a table... i have a command button which then inserts the vaule from the combobox to the textbox.

in the commmand button the vba code used is:
textbox.value = combobox.value

but this only insert one value to the text box i want multiple value one after the other. it just keeps replace the value which is already in the textbox i want it to add on 2 the value in the textbox...

can any1 help me out?
thank you 4 ur time!
purejoker!