Custom page text field question

Using the old .ini files to create custom installer pages, I could set a minimum and maximum allowed length for a text field like this:

[Field 3]

Type=Text

MinLen=8

MaxLen=8

ValidateText=FAIL=Valid SFDC KB numbers are 8 digits long

Using nsDialogs, I can use the function ${NSD_SetTextLimit} to set the maximum allowed length. How do I set the minimum allowed length? I couldn't find a similar function to ${NSD_SetTextLimit} that sets the minimum length. Does NSIS have such a function?

I have no idea how InstallOptions enforces MinLen? You need to validate the field length yourself on page leave.

Edit: It shows a message box as I would expect. nsDialogs will not do this for you.

Stu