Question: Unknown vector with given unit vectors

Hello,
I have another vector problem, and I honestly have no idea how to solve it. (I am not even sure if there is a solution). I tried to simplify it as much as possible (also the attached maple file)unknown_vector.mw

We are looking for the vectors v2, v3 and v4 
Given are vector v1 (with its unit vector e1 and magnitude m1), the unit vector of v2 (e2) and the unit vector of v3 (e3)
From vector v4 we don't have any information.
The following should be true:
v2 = v1 + v3 + v4, with the condition that v4 shall be as small as possible, with the goal to find the combination of v1 and v3 that comes as close as possible to v2. Of course, depending on the unit vectors, v4 can also be zero. But we assume that the given unit vectors can not be changed. 
I would be really grateful for any help. Thanks in advance! 
Roman

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