CustomInit.m

- (void)myInitialization
{
    //do your stuff
}

-  (id)initWithFrame:(CGRect)aRect
{
    self = [super initWithFrame:aRect];

    if (self)
    {
        [self myInitialization];
    }

    return self;
}

- (id)initWithCoder:(NSCoder*)aDecoder 
{
    self = [super initWithCoder:aDecoder];
    if (self)
    {
        [self myInitialization];
    }

    return self;
}