Updated note: My ML310e Gen8 v2 came with a front fan, another difference between it and the ML10 v2. Note: It's noisy at first power-on until it gets through the boot cycle; I'd be really interested to compare that to the ML30.
With that in mind, seeing as HP sells a front fan kit, it may be one of the better options (if you're OCD at least and don't want zip ties) to look at getting this kit, and either adapting the fan to work with a standard power connector (IIRC, the ML10v2 may not have this fan connector) or fit another fan in the mount itself.
Barring that, I'd probably use the ventilation holes in the front of the case and look at using panhead screws through them to mount a fan, and if not all holes match, careful use of a drill. I'd probably add a fan gasket too to reduce vibration.
Edited by LoneWolf, 18 March 2016 - 06:25 AM.