Translating characters error

Well, that font EurofontC is a Cyrillic knock-off of Eurostile. You could replace it with real Eurostile (which most certainly has the u-with-umlaut) and there'd be no visual difference. However, if your client has insisted that you use EurofontC, then a) your client is a fool, and b) you're going to have to use some pretty poor techniques to fake up those umlauts. These techniques are really fragile (composition by a simple change in font size! among dozens of other potential flaws) so maybe you'd be better off doing pretty much anything else:

However, once you've made this monstrosity, you can copy it to the clipboard and replace all properly encoded u-with-umlauts with "Clipboard Contents, Formatted" and all you'd have to do would be to correct the post-umlaut kerning. I still think that the only way forward is to use a different font, but You Do You (or what your client wants, if that's what you have ot do).